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Home My WebLink AboutAPA2120lX1&~~&c §[ID&®©@ Susitna Joint Venture Document Number ,.....Wi::_'.•~..n~......~........~........~~..~._ Environmental analysis of the Upper Su.;itna River Basin using Landsat imagery r;". .-'. , '" ':,' ;"'~. ,': f ~ I~ I..' \.:.~.. Please Return To 10)rDJ r2 n DOCUMENT CONTR0 LJlJ lDJ l.S LS """'"""-~~'-'----~'~""~~"'~";"" for (onversion of 51 metric units to U5.,'Brit'sh customary unit~of measurement consult AS 1M Srandard EJ80.Metnc Prdtl,(t'CUldt',publi,hed by the American Society for TestilJ:~and M.ltf'ri~ 'lIs.1916 Race 5L Philade{ph4J,Pa.l'JlfH. Cover'Devil Canyon lIeft)and '»'JIJnd dam ,1/(', along the 5usilna RiI't'r.I The \~·.II,H1.J ,i/(' I,apprOXimJlel,'4,'1 ~m upstream ;rom Devil Canyon.'fhe Land,al band S Im.Jgf' /1.0.S470-I'J(60)at 'he lOp \hn taken un I August 19;"6 from an ,l/titL/de of appr(}\~ ;mately 920 km and ;\at a scale 01 1:I,U()(),OOO.The bottor.l photographs ,11(' black ,llJd ",h,le c'opi('s of colo:,nlrar('c! photography taken by ,\IASA on 28 lui,' 1977 d.JrinJ.:llmsion .164 lrom a '8.1{)O~1l1 all/Iud".The \cale ul the photograph," I.-I blW{)(I. "~.,~...",'-"''''~---~-------_._--- I I1, j -"-..........--..---._-,.:;tr"'"~-:~--.>:...'..,..;'.: "',"o·•:'~tI'".JL".:"l?';"'_~t..; -._-_.~.-----"_.~,--~,..,-,.,."-'-~--_.."--'"....._--_.~-_.."--"'.._--_._---.'"'~"-_...~--~."-,~,._,-,~.,~---,,..----_...---......, ·..t CRREL Report"BO-4 ........... i ,Environmental analysis of the Upper Susitna River Basin using Landsat imagery loW.Gatto c.l.Merry H.l.McKim and D.E.lawson l/-.q")1,-,.r-,~;rC:a.rC/P1)(l+I ..(i~ January 1980 f·'•1 J\1~1.A..;z..~ DTICi~.,ELECTEh~_,~.-lJ~,_.~".~...')1::80 i 17-...-.'.'-I ~i' "- ,-~-_.-----....._....'.'--..-._..._--._----_..._---------------- i.._...~--,__,,'_';)~.~?~::~;~~;;:i~~:- P,ppMffi lor DIRECIORATE OF CIVIL WORKS OFfiCE.CHIEF OF ENGINEERS Bv UNITED STATES ARMY CORPS OF ENGINEERS COLD REGIONS RESEARCH AND HJGINEERI~G LABORATORY HANOVER.NEW HAMPSHIRE.USA ~pprO'ot>d .or public IPlt'oI*JoP.dlqubulilln unhmlU'd 80 '5 so 027 ,..'r. ,~ --"'."'----_.,-~......._-..--_.._.........~~''"._."'....__..,.."...._...._--<.--'~-----~,,--""'~- .~:'3-;-~""":...::.~/:""--~L ..."'".;0~,~.~_~~;~_....·_4 __~'..~_____~_ Unclassified SECURITY Cl-ASSIFICATtOH OF THIS ....GE (It'h ..D••En ....", REPORT DOCUMENTATION PAGE READ INSTRt:CTIONS B£FORE COMPLETING FORM I.RE:PORT NUMBER JPti9~W?;ONO 3.RECiPIENT'S CAT AL.OG HUMSER CRREL Report 804 - 4.TITl-E (..d Iiubtlll.)5.TYPE OF REPORT 6 PERIOO COVERED ENVIRONMENTAL ANALYSIS OF THE UPPER SUSITNA.RIVER BASIN USING LANDSAT IMAGERY 6.PERFOP...ING ORG.REPORT NUNSER 7.AUTHOR(.)8.CONTRACT OR GRA..T NUloIBER(e) L.W.Gatto,C.I.Merry,H.L.McKim'and D.E.Lawson I.PERFORIIING OF<GAWllATION NAME AND AOORESS 10.PROGRAN El-E"E"T.PROJ~CT.T"SK U.S.Army Cold Regions Research and Engineering Laboratory AR£A 6 WORK UNIT NUNElERS Hanover,New Hampshire 03755 CWM-R·77-j : .avIS 31013-CWE-B·78-10 CWIS 31568 1 t.CONTROl-l.ING OFFICE NAME AND ADDREtS 12.REPORT DATE Directorate of Civil Works lanuary 1980 Office,Olief of Engineers I).NUNEI!:R OF PAGES Washington,D.C.20314 56 14.WONITORING AoGENCY NAME a AODRESS(II dlUe....I......C""lt'Oll/n.Olll ••}15.SECURITY Cl.ASS.(of tIt/e-.on) Unclassified 15•.~~i~Jt,:,eA"'ONI OOInCGIlAOING 16.OISTRI9UTIOH ST ATEYEN T ~of thle Roport) Approved for publi\:release;distribution unlir.lited. 17.DISTRIBUTION STATEMENT (ollhe ab......._/...~In Bloclr 70.II rllU...., I....Ropo<t) 111.SUPPl.I!MaoTARY NOTES I,.KEY WORDS (e-Unuo _.._e••1./I n .....__1"'''1F ..,&10""n....b..' Aerial photography Environffi~ntaJ surveys Mapping Satellites (artificial) lt~....,""ACT ~_..__,,___,ty-.,.1>10."_) /'The primary objectives of this study were to I)prepare a map from Landsat imagery of the Upper Susitna River Basi" drainage network,lakt'S,glacifOrs and snowfields,2)identify possible faults and lineaments within the upper basin and within a 100-km radius of the proposed De,il Canyon and Watan.1 dam sites as observed or,Landsat imagery,and 3) prepare a Landsat-<lerived map showing the distribution of surficial geologic materials and poody drained areas.The EROS Digital Image Enhancement System (i:DlE!:)provided computer-en"anced imagt'S of Landsat·1 ~ene 5470- 19563.The EDIES false color composite of this sce"e was used as the base for mapping drainage network,laKes, Klaciers and snowfields,six surficial geologic materials units and pooriy drained areas.We used some single-band and other tolar composites of Lmdsat images during interpretation.All the above maps were prepared by DO rOAM IJ.....n 1473 EDlTlON OF ,NOV ..'"~OIlSOLETE Unclassi fied SECURITY Cl.ASSIFICATlON O~"ntiS P-"OE r-D ••I!"''''''' .--..-/, c ';cC·~~·",...._-_·------------..-_.__._..__._-._-.. , Unclassified SECURITY CLASSIFICATION OF THIS PAGE(1f!l_D.,.ltnl-.d) 20.Abstract (cont'd). phctointerpretation of Landsat images without using cornputer analysis,aerial photographs,field data,or published reports.These other data sources were used only after the mapping was completed to compare and verify the inforrr.atio interpreted and delineations mapped from the Landsat images.Four Landsat-!MSS band 7 winter scmes were used in the photomosaic prepared for the lineament mappinb'We map~ed only those lineaments related to reporte~regional tectonics,although there were many more Jineame<1ts evident on the Landsat pt>otomosaic.Landsat i",?gcry provided useful information on the major drainage patlc~ns.distribution and reflectivity of lake~,geologic features at the terl'Tlinus of large glaciers,medial and lateral gl2.:ial moraines and geologic 1ineamen~.Interpretation of the Landsat imagery for mapping surficial geologic materials without previous knowledge of the past and present scdimentary environments of the study arca is difficult and the use of the results may be limited.Satellite and aircraft imagery are mure accurate!y interprcted when the interpreter is familiar with L'lc types of envirunments prcsent.Lar,dsat ;magery provided geologic information in a reOlote area q~icklv and cost-effectively.It also provided preliminary planning information and in- dicated regional differences.It wi!1 not.however,supply the detailed site-specific data required for design.Ground truth data are required for all remote sensing inv'.:stigation~using satellite or aircraft data. ii Unclassified SECURITY CLASSIFICATIOOl OF THIS PAGE(lPI>...D••£n,.,K) -----..._"...-----'-'.' ----..,...--_.--_...-~.-----~~~~t~·.~J?~k-~~~:------.---._-_.....~..._.,,._~.--",_.-:------ ,.~~-~--.._._---~~.---._-......,~_.,---,-....,..._-"'---,..,....~~--.,.,,.....--'_...__._------- i· rREFACE This report was prepared by Lawrence W.Gatto,Geologist,Carolyn J.MErry, Geobgist.Dr.Harlan l.McKim,Soil Scientist.and Dr.Daniel E.Lawson, Research Physical Scientist,of the Earth Sciences Branch,Research Division,U.S. Army Coid Regions Research and Engineering labontory.The Directorate of Civil Works.Office,Chief of Engineers,funded the majority of the project under Reimbursable Order No.CWM-R·n-3,Environmental Analysis of the Upper Susit- na River Watershed,sup!Jlemented with additional funds under Rei,bursable Order No C\\II:·8-78-10.Susirna Landsat Analysis Project.The CiVIl Works En- vironmental Impact Work Units,CWIS 31013,Environmental Effect~ar:d Criteria for Engineering Works in Cold Regions.and CWIS 31568,trosion Potential of In- land Shoreline and Embankments in Cold Regions.provided additional office and field support. The authors express their appreciation to Eric Yould (formerly of the Alaska District>.Glen Greely of the Alaska District.and Gary Flightner,U.S.Army Engin- eer Div!sion,North Pacific,for assistance in formulating the project objectives; to Dr.Jerry Brown,a,.d Richard Haugen of CRREL,Vern Thompson,Alaska Dis- trict,and Glen Greeley for technical reviews of this report;to Eleaf10r Huke for assistance in preparation of the mapc and figures;<md to Dr.Brown and Thomas Marlar,CRREL,for technICal suggestiom and comments during the pro/ecl. The ccntents of this report are not to be used for advertising or promotional purpo~es.Cftatlon of brand name~does not constitute an official efidorsement or approval of the use of such commercial products. '-._---....--.--,--"' iii '"~Y!~·.~~~·~.Y~·~:.S·a ..,4cC8U1oa Fol'JilrISGi"-..r..aI ~.....l'!OC UI I- ~OW2ced '"'"J\atU'lc;;rUon ..... By D1strl!-uf.1.('~1~- __Avfl1l~?ll!.~l-Cod~sIr"~""10'DR 'PT' -_........~,...-..L__'..~......~.'-_. •..'o't'._.•..:..'1::,....,......::.-...;~,-:.:.....-,.r::..:...J .......__,."".~ ?ag~ i iii vii vii vii 1. 1 1 2 2 2 3 lakes. 6 6 6 6 22 I I -..,..~.~---....~...,...---"--_.... CONTENTS Abstract Pref ace Summary . Objectives .. Conclusions Introduction. Background Previous cooperative investigations Project rationale and coordi:lation Approach Landsat imagery Interpretation techniques Part I.Use of Landsat imagery in mapping the drainage network. glaciers and snowfields (Lawrence W.C.llto) Objective Methods Results Conclusions Part II.Use of Landsat imagery in mapping and evaluating geologic lineaments ~nd possible faults (Carolyn J Merry)24 ObjHl,ve 24 Geologic st~ucture 24 Methods 24 Resul~24 Conc lusions 27 Part ill Us!'of Landsal imagery in molpplng surficial malt·rials 29 Section A.Landsat mapping(Harlan L.McKim)29 ObJPc lIVe 29 Methods 29 Results ~I) Section B.Field evaluation (Daniel E Lawson)31 Objectives 31 Methods 31 Results 31 DiSCUSSion 32 Section C.Conclusions(Daniel E.Lawson and Harlan l.McKim)34 literature cited 36 Glossary 39 iv I J I, t·..&:',..~.::_::..~."::':..'~~'~::.~-~~,.................~""f......\.'f ...~~~_..;~w~L_~___.__.:..-_.__,--. :..: --,,-...~......-~~.,,-~~,~__......_.._...=-._:._~i:..-.._.....Q ......-~"*~.~......'>&....._~..~----.:.~.....~..",'"'~,;,'--"~ ILLUSTRATIONS FIgure 1.Upper Susitna River Basin and hydrometeorological statiom within and near the Basin 2.locztion of the EDI':S prOGuct and the photomosaic used for mapping 3.EDIES false color composite of scene 5470-19560 taken 1 August 1976. 4.Single band EDIES imag~s of scene 5470-19560 5.Confluence of the Susitna (2)Jnd Maclaren (1)Rivers 6.Channel bars (1)and islands (2)in the Susitna River upstream from the Watana Creek (3) 7.Drainage network,lakes,and glaciers and snowf;elds in the Upper Basin 8.Drainage netwcrk,lakes,glaciers,morainal areas,channel bars, and swampy areas on the USCS Healy :opographic map 9.Big lake (1)and surrounding area 10.Area between the outwash plain (1)of West Fork Clacler and Butte lake 11 Area near the confluence of the Susitna (1)and Tyone (2)Rivers 12.Ar~a b~tween Maclaren River (1)a:ld DIckey Lake (2)in north- western part of baSin 13 Cle3rwater Creek (1),Maclaren River (2),and Denal i Highway (3) 14.T(~rminuJ of the West Fork C lacier (4),exposed ice (2),meltwater streams (3).debris at terminus [1 I,surface water (51,Nenana Cla- cier (6) 15.East Fork ClaCler(l) 16.Terminus of the Susitna Clacier (1) 17.Site local'9n map of the Upper Susitna River Basin,Alaska 18.lineament map of tt:e Upper Susitna River Basin 19.Kn~wn faults map of the Upper Susitna River Basin.Alaska. 20 Map of northwest North America showing maim tectonic factors 21.Epitenter locations map of the Upper Susitna River Basin,Alaska 22.Exp/or"tcry soil survey map of the Upper Susitna River Basin, Alaska. 23.Surficial geologic materials as mapped !rom Landsat imagery and field site locations. v Page facing pg.2 4 5 7 12 13 facing pg.14 15 1& 17 18 19 20 21 22 23 facing pg.24 following Fig.17 following Fig.18 26 facing pg.26 facing pg.30 following Fig.22 .t.__~-...~..~~,.....1'reO,&it .........-~',.~'::-~_.t...'6'''".te··..,• .. ·"".__.."..__._......._,~..._._~,__~_-_..,w _ Figure Page 24.Aerial photogr..~~showing region near Denali Highway (1)and Clearwater Creek (2).33 TABLES Table 1.Cloud cover,seven-year mean value from 20 stations in Alaska 3 2.Compilation of earthquakes with a Richter magnitude ~4.0 from March 1975 through December 1977 within a l()()"km radius of the Devil Canyon and Watana dam si:es 28 3.PrevIOus geologic mapping in the Upper Susitna River Basin.Alaska 30 vi \.__.._'.::::::::~:.:-----.--_..-...-.",\!.·r :~·:"'¥-;.i+"..li~....,;.1i-:;:':~ ...:: ._._.___..•.__•.~•...•..__..___..•_w.~.••._•.._".._._._.__~ SUMMARY Objectives The overall objective of this investigation was to evaluate the utility of environmental data derived from the interpretation of Landsat imagery for preconstruction planning i'nd design of the h,droelectric project proposed for the Upper Sl;sitna River Basin. Specific objectives were to: 1.Prp.pare a map from Landsat imagE'ry showing the upper basin draina~e network, lakes,glaciers and snowfields (Part n 2.Identify pos~ible faults and lineaments as observed on Landsat imagery within the upper basin and within a 1QO-km radius of the proposed Devil Canyon and Watana dam sites (Part II). 3.Prepare a Landsat-derived map showing the distribution of surficial geologic materi- als and poorly drained areas (Part iliA}. 5.Evaluate the accuracy of the Landsat·derived surficial geologic matenals map by field investigations at selected sites in the basin (Part IIlB}. 5.Cooperate and coordinate with personnel from the Alaska District in evaiuating these data products and those developed during the Bureau of Land Management (BLM}-National Aeronautics and Space Administration (NASA)Applications System Veri- fication and Transfer (ASVT)Project. This hydrologic and geologic information should be important in preliminary route and site selection,in bedrock and SOils analysis,and in locating construction materials,e.g. glaCIal till,sand and gravel,and quarry rocks. Conclusions Landsat imagery provided useful information for the Upper Susitna River Basir.The major drainage patterns and the distribution of lakes in the basin were clearly shown on Landsat imagery.Many small lakes not shown on available 1 :250,000 topogrzphic maps were evident on the 1 :250,000 landsat imagery.The imagery also showed differences in the reflectivity of the lakes.The shorelines of some of the small lakes,however,were not w£ll-defined on the imagery. Many geologic features at the terminus of the large glaciers in the upper basin are well- defined 0'1 landsat imagery.The medial and lateral moraines of the glaciers are also ap- parent.Changes in these features could be documented and analyzed using repetitive coverage ot landsat imagery. Landsat imagery would be a usefu;tool for updating large-scale maps of river channel configuration and location,midd,annel bars and islands,location and features of the glacier termini,and for monitoring changes in river and lake sediment concentrations. A predc.minant northeast-southwest set of lineaments and a secondary north northwest-south southeast set appear on the Landsat imagery in a 1QO-km radius of the vii l ;:..~:;y.'i'};~~~'~~';',..~",,~ '.--------.,,--_._-, -"-"'"'--'~....-._,-".._~-,.-..."~._,,,,.,..~,.,~,,,.,-.....-.",-,--'.......,_..-'---".•~..~....,-_.-...,....__.......''''.....__.~-''''''''',.--,,-~-~----_._--- Devil Canyon and Watana dam sites.The predomi~Jnt lineaments are associated with:1) the Denali fault zone,2)the Cretaceous to Recent f<luit zoC)e.and,3)the Talkeetna thru>t, The surfiCial geologrc matenals map shows th"dlstrobution of SIX general materials units: b in-SItu bedrock and very coarse,rubbl\'~)edro<:k colluvium. bc coarst'-to fine-grained deposits occuu;,-,g on moderate to steep slopes, ag undifferentiated alluv.al-glaciofluvi,d 0epos/ts. f/,l.nd,ff"rentiated fluvial-lacustrine depus,ts, tl,fI,deposits,e"cept wIth iewer lakes and not as poorl y dr ained. urr unvf'getaled morarnes The l;bc,(f ..f/J.and um l'n,ts were eas:ly diffen-<ated,the ag unit was difficult because it had many tonf'S dnd te"tures on the Imagery."";,cial geologic materials mapping took les5 than 80 hours. T""fll·'d Inveq'gatlons fo'the Landsat-dt'riv'!·j surfIcial geologic materials map in- d'cate that .nost largt'areas at exposed bf'(jrod '.'re cleiHly dIstingUishable from uncon- solidated depOSits.As expt'cted,scattere"onsol,dated dt'posits surrounded by bedrock wert'not recognized by Lan(~sdt Interrl,~:,Inn AredS of unconsolidated deposits in which small bedrock outcrops are common V,".t'not dIstIngUished from Meas without such outcrops. The typE'S 'lnd origins ·)f un(o,,~()I)(j.1lC'd '.:._:('riAI~deposIted in the glacial and periglacidl environment co"id nct be c!edr1v det""d with the Lands.1t imilp,ery.This was particulMly true for .:Ireas of till ,'nd olher sed";,,,,,!ot Similar te"ture and sorting which were mapped mdinlv as water-IJld sediment; Interpretation of the Landsat Imal-wry for mdp:);n~surfiCial gt'ologlc materials Without prevIous k'nowledgt'of the past dnd prespnt st'th:·,pnt.Hv environments of tht'study Mea is diffIcult and the use of the re,ults may be I:mitl'd.Sa!elJite and aircraft j,nagery are more accurately intt'rpreted when the mterpreier 's lam/liar ....lth th(>types of en- vironments prest'nt.Ground truth IS always r{'('pred for detailed studies no matter what type of photo base is used In the .nterpretat!on."",thout ground truth,the accuracy of a surficial geology map cannot be determIned.Jnd therefore care must be taken when using information derrved from lanasat imdgery dlone The information can be useful when regional geologIC informatIOn 's limited or unavailable. Landsat imagery provided geologic information In a remote area Quickly and cost effectively.It also provided prelimInary pl.lnning informatIOn and indicated regio:1al dif- ferences It will not supply the detailed site-specific d3ta rt'quired for design.Field data are required for all remote sensing invest:gations 'Jsing satellite or aircraft data. viii t ---.....,.-__-_~~_.~_..~•.-,.~----......_----_....~--~.~~·~-v;~'",..::_~;_ ,"..-,-,..,,-,~------<--._....-+'..-_..-",~"--=•._--_."'....._,,-_...-'--,.,~•._'............-_....- ENVIRONMENTAL ANALYSIS OF THE UPPER SUSITNA RIVER BASIN USING LANDSAT IMAGERY l.W.Gatto,c.J.Merry,H.L.McKim and D.E.Lawson , ~ INTRODUCTION Bukground Plans are curren~ly being considered for devel- cpment of the hyc'roelectric potential of the Up- per Susltna River (Fig.1).These include the (on- structlon of two dams and related facilities,i.e. powerplants,t'lectric transmission works to re- gional load centers,access roads,and ~erma nent operatin!:and recreational facilities (U.S. Army Corps of Engineers 1978a) The environmental impact statement (US)for the Upper SU>itna River region is a comprehen- sive assessment of the proposed project and states the r,otentlal adverse environmentai ef- fects As stated In the EIS (U S Army Corps of E:lgineers 19751.however,because "the current study is in th~feasibility stzge.Impacts are not exhaustively evaluated.If the pro;ect IS author- ized and funded for detailed studies,environ- mental,social,economic and en~~inee"ng as- pects of the project will be studied at length prior to a recommendatIon to Congress for ad- vancement to Lnal project design and construc- t'on." The follo"ling environmental topics were felt to warrant more detailed investigation:soil and permafrost characterizations,structural and sur- ficial geology,potential influence of river flow regulation on floodplain vegetation,ice forma- tion and jams.land use,water fjuality and snow hydrology.This p"~.ect was initiated to il!us;r<lte the use of landsat imagery in analyzing some of thpse topics Previous cooperative investigations Bilello (1975)rep0rted an analysis of the regional winter environment in the basin.'Oat'! were collected and analyzed on the winter clt- mate and on the snow and ;ce cover from Na- tional Weather )ervice records.The objectives of thiS study were to 1)combir,!'available in- formation on wmter surface condition~,2) assemble maximum coverage of rec:::nt weather ciata,3)group weather records for all statiolls for a concurrent period ~o that comparisons of the data between stations woud be possibfe,4) compile information on ,nowfaJ:amounts dnd snow depths,densities,and Ivater cquivalents,5) gather data on Ice formation,growth ,Inc!decay on the rivt'rs and lakes,and 6)r(~\'lew and presenr the data in a form suitable for quick use and easy referencc. During 1974,1975 and 197&,CRREl and lhl' Alaska District collaborated in evaluating tht, utility of the landsat Data Collection System If! the acquisition and transmission of hydromete- orologlcal data from the proposed Devil Canyon dam site in the Upper Susitna River BaSin (Haugen et al 1979)CRREl and Di~trict person- nel installed a landsat Data Collection Platform (DCP)at the site in October 1974.The DCP wa~ interfaced With the follOWing sensors:two ther- mistors (one to measure ground temperature,t~e other,air temperaturel,an anemometer,and a snow pillow to measure the water eqUivalent of the s ·lack. The L.JCF was installed to determine i:"opera- tional capabilities ;n a remote cold regions site -----~...._._--. .•..~~~.:~/~..~''",~::.:~.::.~~~:.:"..~.~.:."...............~-t,..~"'..#.Jt •.Jl'it:.."':lo:."Y"~I ... "."" r:--.::f'•.., ......-.__._..~_...•__._.-'.._-----_...__..._.""".__.._---_._._--_._--------- ,lnd to supplement exisling dolta dcquired from the hydrometeoroloKicdl st':llion network within the basin (Fig.1).Haugen el .11.(1979)rpported Ihe result~of this t'vJluallOn. Project rationale dnd coordindlion Coordindlton with the Alaska DIstrict for the Llndsal tnvest'l.:atiun began tn Novem!wr l'l7'l whl'n we were ,mtiJlly formulrlill1g the ob,ec- tives <lnd dppro.lch The actual investigations bet-:.In tn April 1477 whpn funds wprp rE'celved from Ihe OffitE'.Chief oi lnginpers. It was in,t",lIy at-:repd betwPl'n CRf{El .Ind the AI.Iska District that the projPct would lll',IC complished uSIng oniy landsdt Imagt'ry Ir,ter· pn'trltlon without ground truth to vl'rify tl1l' Illdppl'd ip,lture.Tow ..1rds the l'nd of the p:ulel"l we deuded to obtain ground truth to .ISS,'SS thl' ,lccur,lcy of till'sur"ci,l)gpolo!iY m.lpptng units. This was dccompl"hed w,th .lddlt,Olhll funds durll1t-:the SUfllnwr of 1 'J78. Intllrll coordtndtlon ml'etings with ~)(-'rsonnl'l from tlll'Djstrlct.BlM.NASA.Unlvpr,ity of AI,lsl..a (UAJ.l f<OS 1),1!,1 Cpnter ([DC).U 5 Fish and Wildltft,S,'r"it t'(F\V51.,Ind U 5 St,,1 Cansl'r· v,ltion 5l'rvile (5('5)WP;('held from 2.7 I\pril to 'l M,ly 1977 1 hI'prowct rl'qulCl'd do\('taordin.l- tion b"twl'l'n reprt'wnt.,tivl's irom t~1'District, eRRl I.,"nd lilt'othl'r <lgl'n('II"tnvalVI'd in till' Appil(.ltlon,Systl'm V"fli,(,ltlon ,\ml 1 r,lnsfl'r (A~;.'T)prow,I.Addltlon,Ii ml','tll1g,and dis· CUSSI<H1'with <111 pMtll',O(currl'd p"flndi,,Illy throughout till'H1Vt·,tlg,llllln 1 hI'A5V"pruJl'l!t'v,llu,lted Irl dl'l,1I1 thl' typl's ,ll1d ,1('cur,lcy'ot Ir.10rm.llum on g('ology. g('ol11<Hphology ,\I1d Vl'gt't,lt lOll thde ,1ft'ob- t,llll,lbll'frol11 Ll nl!s.l I IIn.lgl'ry ,md IHulli",tit' ,ll'fI.11 photogr,lph,l\V,JlIt'r 1977.0(',\11 1'l7'l). Till'.ASVT projl'et ,it I'Wrl'restflcll'd 10 th~,Ilor- thl'rn portion of Iht,lIPPPr SlISlln,l :{IVl'r Il.lsin, ,md thl'.If,',l west .1~d ('.l~t of 1111'b.l\1n .llong tht' Dl'n.Jh Hlghw.JY. APPROACH Ldndsd t im.lJ;:ery· Satellite orbit,ll characl('ri~t;cs l.l£1d',1l-2 .Ind -3 ,lfl'cllrrt'ntly opi'r,lling in 'llll-km m·M·poIM (',l'rlh orbits"',H.h soIl ..llI(t, •H"..,·d 011 Alldl'p"on ('I .iI (It'7 Jl •·1.111~".'I·l (l~)t'r ••tuHl',..,....Ir'lniln,"t'd on h 1.\IlU,U\1l)7t\ z completes 14 orbits per day,Ihree over AldSkd. Each orbit tdkes about 103 ml£1utes.ThE'orbils over Alaskd on l',lch day MP adlacent and west of the previous day's orbits. Because the l,lndsat n':'ar-polar orbits con- verge toward thl'poles.Ihere IS apprux.mdtely 60%sidelap on the imagery tilken on ~u.:cessive ci,IYS ,It the high latitudes of Alaska.ThiS mll'ldp .Jllows thl'Sdme pomt in Alaskd 10 be covered by Pilch landsat on three successive days The or- bits ,11~0 permit repelitive coverage of dny areil 111 the world at the Srlme local tome every 18 d~ys Multispectral scanner L1Ch sdlelille carries two imdging systems,a multlSppctr,11 scanner (M55l ar,d a return bE',lm vldic~>n (RIlV)We used only the M55 Imagery for thIS mvestlgation. The M55 is .I line scanning device that pro- vides images of an area approximately 185 km square.Each image COnsiStS of many individual picture elements (pixels)that are obtained in rapid sllccession by means of an oscillat:ng mir- ror bl'hind the lens of the MS5 (NA5A 1972)The oscillating mirror SCdns a 1 85-km-long swath per- pendicular to the spacecraft path.The MS5 simultaneously records in four spectral bamh the dmoul1t of light being reflected from a 58-x 70-m dfea of the earth's surface.the size of one pixel.The four spectral b,1£1ds are:band 4.0.5-u.& /-lfll (blup-green),band 5,0.&-0.7 J-Im (yellow-red). band b.0.7-08 flm (near infrdredJ,and band 7, 0.8-1.1J-1m (near mfraredJ The M55 video signal is converted to digital ciata Jnd telemetered to a receivmg station on I'arrh,either in rea!time or after being recorded onbodrd The final data products include com- puter compatible tapes (eCTs),black and w~lite photop,raplls of individudl spectral bands (bands 4-7).and color composites compfisinK several bands,usually bands 4.5 and 7 or blinds 4.5 and b. Gray tones A 15-step gray scale appears on every Landsat image The gray scale shows the relation~hip be- tween a level of gray on the image and the elec- tron beam density used to expose the original image The electron beam density is related to (he energy incident on the M5S detectors.This incldpnt E'nergy is related to that reflected from features on the Earlh's surface The variations in incid<'nt enE'rKY produce the tones.textures,and --------c·~·~~~i<~~'.jA.Ci~'~·~S;" --~.---,. ~..--'~---""~."'.."-'~-'--'---"-""'"'"-'"...----""---...-.-- /------~"\ ~\\ ';)0 '~"'"\/\!C?-"~~< (""..);: ./</ //~~.......' c;~ LEGEND Rive,Gauging Slati""(USGS,COEI "ilh W.ller Quality CliMldlic Stdtion<(NOAA) Snow Cuu"es/Od'd Meds..rjn~Sites (SCS) Sno...C"lIe,Mea5u<err.enl Location (CRR£UNOAAj Rive,Icc Thickness Sires (USGS) Figure 1.Upper Susilna River Basin and hydromete- orological stations withIn and near the Basin. •'"• on. ~ \i ....~t/l 0,"" 0:.- 0-0," ><Fj i~~U~ 0~ ~~gj o -"-~-·--··r :.~\~/;~·~:!',.0j.;.~·~~·.":~~'" 'Sui...0 (rlearllO 10 (complete (loud Lover) patterns on the Landsat imagery that we used during photointerpretation. Table 1.Clo:Jd cover,seven-yen mean value from 20 stations in Alaska (Anderson et al.1973, p.4). Sun elevation effects Changes in the local sun elevation angle cause variations in the illumination of a particular area.When the sun angle is low,solar illumina- tion tends to enhance·topography,and geomor- phic detail of topograohic features is more ob- vious.Features with small topographic relief are generally obscured when sun elevation angles are low. Interpretation techniques We decided to use manual photointerpreta- tion techniques rather than automated inter- pretation for two reasons.First,the manual techniques require less sophisticated equip- ment.The imagery can be easily obtained and used.Consequently.scientists and engmet'rs in the Corps'Districts would be more likely to use photolnterpretatlOn themselves before be- coming involved in more advanced,automated computer analysis techniques.Secondly,the BLM-NASA ASVT project inclup.!d extensive use of computer techniques for al.alysis of L,lnd- sat imagery.There was no need to duplicate their E'valuation and dE'monstratlon of computer techniques. The same photo;nterpretatlon technique was used ior .lll parts of thiS mvestigatlon The Al.lska Dislrlct dnd CRRa agreed that the drainage network.lakes,glacier,and snowflelds, I,nedments.dnd surficial geologic materia~s were to be mapped solely on the basis of tones, textures and pattE'rns viSible on the Landsat im- agery.In some cases image sidelap permitted stereo vieWing.We latc'r compared our maps and observations made strictly from Landsat in- terpretations to pubbhed maps and reports, aerial photographs,and ground survey data. Usually geologists milke limited ground surveys prior to geologic mapping to become familiar with site-speCific geology,and then use satellite and al?rial Imagery te prepare regional maps.ThiS field-t'J-reglonal approach was inten- tional/y not followed in this stud",.so that the Landsat imagery alone could be interpreted and evaluated. The aerial photographs later used for com· panson with the Landsat interpretations were taken on 24,28.and 29 luly 1977 (NASA MiSSIOn Snow cover A snow ,=over enhances certain topographic features not readily apparent without it.Snow enhances fore5t boundam:s !Jut obscures low vegetation.Many subtle relief features such as glacial moraine topography,thaw lake morphol- ogy and riverine features are better defined on images with snow cover than on snow-free Im- ages of the same area.Wobber ,lnd Martin (1973) report that a heavy blanket of snow (>22 cm)ac- centuates major structural features.whereas a light dusting «2 cm)accentuates more sub~le topographIC expressIons. S"1,"'m!wr P,{) OrtotH'r 7 'J ."Iovt'mbt><7 7 DpCl'n;bt><7 4 May 7.7 I un..110 July 84 Au~u'l 8 j January £'7' February 7 2 March 70 Ap,,1 7.2 Cloud cover A major limitation in the use of l.andsdt Im- arery for environmental studies in Alas:"a is cloud ~o ...er.Cloud cover statistics from 20 sta- tions in Alaska averaged over a spven·vear period showed that most locations avera!4ed more lhan 70%cloud cover throughout the year (Taule 1).Although the cloud .:wer rna\,not always be opaque to the MSS.a thin cloud layer partially obscu res surface fea tu res and detaIl. and interpretation becomes more difficult Resolution and positioning The smallest circular.oblate or rectangular object detectable by the MSS can be no smaller than 58 x 70 m.It is,however,possible to identify smaller linear features such as streams,transmIs- sion line right·of-ways,drainageways and road networks when the contrast between them and the surrounding terrain is great. The approximate geographical location of features relative to one another may be deter- mined directly from the Landsat imagery.An ac- curate positioning of features is also possible when the imagery is used in conjunction w:th uses 7.5-or 15-minute top::>graphic maps. 3 l__• .__,,-~:~~;':,i;~~~~ii;;~~;~ '·'""~"'__""'__.C··4_'-"··_""'''''__'''''''';''·''''~_~-.-......."..,....""'...-....,,_....#....~,~.<..........,.....,,~", 304.Project 565)with two Zeiss metric cameras with lenses of 15-cm and 30-cm focal length from a NASA WB-57 aircraft along 14 flight lines at altitudes of 9100 m and 18.200 m.Film was Aerochrome Infrared (2443).The p!1otography was obtained by NASA in support of the BlM-NASA ASVT project The feature identificatIOns and mapping dIS- cussed in Parts I and IliA of this report were done from the 1:250,000 scale tDIES'color composite photograph (Fig.2 and 3)used for the mapping base,the E01 E5 single band images of the same scene and other standard landsat im- ages at various scales. Possible faults and lineaments (Part II)were mapped on a photomosaic (Fig.2)made With 1:250.000 scale enlargements of standard land- sat images obtained in the winter of 1972. During the field observations in 1978.the NASA aerial photographs and the EDIES color composite were used to -:heck for characteristic tones and textures of unconsolidated sediments (Part IIIB). Some of the standard landsat images were photographically enhanced .md enlarged from 'llJllS IROS lJl~.ldl Imd~"Inhdn<~m~n'SV'I~m.•11 ,hI' U S Ct··olo~IC..d1 Survl'v l ~os.U.JtA L...nll~r.SIOll"~.111,.Souln lJ.lkotd 4 A -SUltina RI¥.r 8asfn landsat Mosaic e-Susitna Ri¥.,eas;n EDI ES PrOduc t Figure 2.Location of the EDIES product and the photomosaic used for mappi.'1g_ 7D-mm and 184-mm POSitive transparencies. High contrast printing techniques were also used to enhance the contrast and the topographic relief in the baSin on ~ome of the low contrast landsat images. '......ax......Jli ............a--..._..---.-.-----_.----~---.---'.'r ~-..~~:~r.~~~~~~...~: ..J ....., ·9L61 I sn8n v L ua,/['l 09S6/-UU-S aua)~/0 al/sodwo)JOIO)a'I!!/51101 ·f iJJIl~!J ._-""._.._,_...•--_.,._-""------_._-------- PART I.USE OF LANDSAT IMAGERY IN MAPPING THE DRAINAGE NETWORK, LAKES,GLACIERS AND SNOWFIELDS lawrpnc('W.Gallo Objective The objective of this portion of the study was to map the drainage network and distribution of lakes,glaciers,and snowfields in the upper basin from landsat imagery.The map was then evalu- all~d by comparing it to available maps and aer- ial photographs.These typ('s of data are impor- tant for analyzing the basin drainage network, and for estimating runoff volumes,timing.and the water retention characteristics of the basin. Methods A computer search showed 561 landsat-1 and 328 Landsat-2 scenes available for the upper basin as of March 1977·.I selected the scene for use as the mapping base contingent on the per- CEntage of the baSin shown on the image. amount of cloud cover,time of the year,and date and quality of the tn-"'ge. landsat-1 scene 5470-19560 was chosen bp- cause It was dcquired on 1 August 1976,showed most of the upper baSin,'was virtually cloud free, showed vegetation dunng maximum growth,and was of high quality. I used an EDIES fats('color composite (Fig.3) of this scpne as the mapping base because the EDIES products are the best computer enhanced photographic products easily obtainable by Di- trict personnel.The EROS Data Center prepa:ed the composite from bands 4,5 and 7 data and enlarged it to an approximate scale of 1 :250,000. Before interpreting the landsat imagery,I transferred the boundary of the upper basin to the landsat image mapping base by visually fit- ting an overlay of the bounddrY traced from U.S. Geological Survey 1 :250,000 topographic:maps for Healy,Ml.Hayes,Gulkana,.:lOd the Talkee- tna Mountains. 'ldn<hd,·j Wd'Idunch"d on )II.\dr<h 1978 6 The overlay did nO(always fit preCiSe.,over the EDIES base due to slight sCdle variations be- tween the base and the topo~raphic maps.Con- sequently,in locations where the fit was poor, the boundary was drawn free-hand by compar- ing contour data on the topographic maps to re- spective features observed on the Landsat photo base.In the three locations where the boundary goes off the landsat base,I simply traced the basin shape from the overlay. During the interpretatio.l,I occasionally re- ferred to the single band EDIES images(Fig.4a-d) of scene 5470-19560 and the single band and col- or composite images of lands<:t-1 scenes 1103- 20511 (3 November 19721,1408-20441 (4 Septem- ber 19731,and 1768-20345 and 17&8-20351 (30 August 19(4).PrevIous mapping studies (Ander- son et .11.1973,Anderson et .11.1975.Gallo 1976, McKim et .11.197'),McKim et .11.1976.1,McKim et .11.1976b)had shown that different typ('S of hydrologic.geologic and vegetative mformation could be obtalnpd from multispectral images as single bands or as composites I prepaH'd all maps by photointl'rprPtation of Landsat Imdges without uSing (omputer analy- SIS,aerial photographs,field data,or Dublished reports dunng map preparation.These other data sources were used unly after the mapping was completed to compare dnd venfv the infor- mation interpreted ,1Od delineations mapped from the landsat srenes. Results Observations Band 5 images provided information not ob. tainable from band 7 Images and vice-versa. Band 7 always showed the water-filled portion of stream beds.which was not always possible with the band 5.Thp contrast between land and waler on the band 5 Image was not always sufficient to differentiate the shoreline This cuntra~t was usually more apparent on band 7 Cons€quently, both band 5 and 7 images were used during the mapping. The tones of the river anll lake water on the EDIES color composile (Fill:.3)were variable. These vanations may result from differences In ........#~--_.-~~------~-----.'-_._--.".;"~.~~~,;i_~~;~: ------..------,,----., ",-.--,--_..----,..__.._,..--.~_._-_._-----, a.Band 4. Figure 4.Single band EDIES images of scene 5470·19560, 7 ...'.....-.._...-.--....--~_..~ ..~.~-:.~i-~:·........~·;~=-:.=:.:: ---------....,-----~------...--~."..-,....---•.•_......~-~--_-..:-....'.....~.,.......•._-,.-~-<.__.,,.--~_.,,,......~.-y .._j.._.,..-,......--~-.,........,••~~--., ---_._._._.-- .4 =A,4 6 ,,:E•.+,::::a • ------_.._--"-....-~..---- • I I j 09PU~8 0) OL 40'40 --,.._ I Ir ".'~"'''''-<-~'--'-~''-''-''-''''·-.....·"'"....--__""~_f.....,_'",'l>,.,',_••....,"".,'_""1.,,""'-.._....._.......~.".__.,.•__......<.... \.. t suspended sediment and organic material con- centrations.or from changes in the amount of light reflected from the bottom of the river or lake. Deep water with a low suspended material concentration generally appears dark blue or black,whereas deep water with a high concen- tration of sediment and organics will appe.H light blue. Shallow water,which allows a large amount of sunlight reflection from tne bottom,.lppears light blue,although some of the light tone may also result from a hil;h suspended material con- centration. In some cases relative differences in lake water depths can be inferred from the melt pat- tern of the ice cover (Sellmann et .11.1975).lob- served ice in some of the lakes on severa'of the spring landsat images.Depending on lake dl'pth and bottom configuration,the ice cover distribu- tion may correspond to the deep portions of lakes where water stays below freezing tempera- tures longer than in shallower locations. During a cursory examination of the EDI~S mapping base .mage,I observed highly reflec- tive objects in some of the stream valleys and in- itially thought that they were river icings.How- ever,after further discussions I concluded that these features were more likely stream channel gravel or sand bars.Verification of these fea- tures on NASA aerial photographs showed that the reflective oblects were channel bars. Some of the lah~s which were apparent on landsat-1 scenes 1768-20345 <lnd 1768-20351 ilC- Quired on 30 August 1974 were not ilpparent on the EDIES mapping image taken on 1 August 1976.Suspended sediments in the lakes may have differed between 1974 and 1976,causing them to resemble exposed depOSits on the 1976 scene. The landsat Imagery clearly jhows the distfl- bution of braided channels on the glacial out- wash plains,midchannel bars and Islands In the Susitna River,and differences in suspended se(lI- me"t concentrations in the basin f1v~rs.NASA photograph 1&-060 (Fig.5)points out the tonal differences (3)between the Maclaren (1)and Susitna (2)rivers that were apparent on the EDIES base (FIg.3).Also,the bars (1)and islands (2)apparent on the landsat scene and'the NASA photograph 16-()4()(Fig.Il)are VIrtually identical in general shape and in loration alan!:the chan- nel. It was also possible to ohserve the chan!:ed locations of some channel bars,and that melt- water stream locations had changed near the ttor- mini of several glacier~. Drainage network The drainage network pattern of a baSin indi- cate~the Influence of slope,differences in bed- rock,structurill control,recent tectonism,and the ~eologic and geomorphic history 01 the bas- in.Therefore,con~iderablegeologic mformation can be Inferred from the drainage nEtwork.The dralOage pattern can be used in analYling geo- morphiC features.This analysis is helpful in un- derstanding structural and lithologic control for land form development (Thornbury 1954). When mapping the drainage network,I mapped streams and rivers that were visible on the landsat images or that could be inferred from vegetation pallerns (Fig.7).Frequently, stre.:m or rivl"r water was not evident because the qreams were intermillent,very shallow,or very narrow.In these cases,I inferred that streams were present when there were well- defined valleys.These valleys usually occur in the mountainous or hilly portions of the basin, are stecp-sided,and have little or no floodplain. Stream channels that.were difficult to distin- guish in an'as of low relief were not mapped. I Included the midchannel bars and Islands along braided rivers ilS part of the river (Fig.7) The small individual channels·that com [JOse .1 braided river were not delineated sep<Jrateh,...As .1 result,downstream from a glaCIer terminus. the dr.lInage m,lp shows the active floodplam, not 11I,t the river channel. The overall drainage paltern of the upper Su- sltnil Riwr BaSin is dendritiC (Fig.7).Usually.the <lngh's of confluence uetween streams are can- sider.lbly less than 90°.Except for the two Lends of n('ar/y 90°along the Susitna River bHween tht'proposed dam sites,most of the malar rlvpr confluences within the basin are considerably less than 90° Typic,llly.iI dendritic pallern develops on rocks of uniform resistance where most of the dralnilge is not struCl.urally controlled (Gdfuly et al.1(68).Usually,the lack of structural control is tound in iHPas with nearly horilont..,sedl- menlary rocks or massive igneous rocks,or With foldl'd or complexly metamorphosed rocks when thl!river is superpmed (Thornbury 1954) I n the central portion of the basin between Big lake on the west and the inside of the large loop on the Susitna River,the drainage appears to be 11 ,-._--_._..----.---------~-..-~·,...,·i·6~~"~~....·-._----_._.-......--.---.--, Zl '()(I(J'(J9t'l 'al!?Js :,.9f UOISSIW VS\lN ilulJnp LL6t '~/nl 111 uo 'Jd~['1 :/r/dJuaJdll'p Il'UOI dJOU :SJ;J,\I?i (II UdJl'fJ['j,V PU!?(n t'uJIsns d41 /0 dJuan/luOJ '5 i3Jn8'J "000'U91:[';J/f?)S :t9f UO/HfW VHW fJuunp LL61 I\/n/9Z uo U;J'IPI :([)'1;JillJ PUPjPI\;,ilYJ WOll WPilJlsd(]J;JM~eUI/S(]'i ;Jyl UI (lJ <pue/s!pue (0 5Jeq /;JUUl?4J "9 ilJ(]SU { , J r ---------_.~._--_. """--""'-'---,~"..._-'_.."'~~-'---'._----."--_.....,....,----_._--_.~-----"---------- , J ~-..~..-....,~.'~ radial..Radial drainage patterns have streams di- veq~ing from a central elevated area,i.e.a dome. volcanic cone,or some other isolated conical or subconical hill (Thornbury 1954).The radial ap- pearance in this basin may result from this clas- sic type of topography or it may be a result of the Susitna River bending around these central uplands ann receiving runoff from both sides (Dean 1979).This would result in a radial ap- pearance. 'Oetween the source area of the Oshetna River and Susitna lake,a sr",,11 portion of the drainage pattern resembles a parallel pattern.Parallel patterns typically occur where slope or structur- al controls <He strong.These controls cause regular sfJacing of parallel or near-parallel streams (Thornbury 1954). The presence of three different drainage pat- tern~is not surfJrising because of the complex geologic history of the baSIn and its large area. approximately 16.210 km'. I compared the landsat-derived map of the drainage network to the Ul;Geolc glcal Survey hydrologic overlays use to prepare the 1 :250.000 Healy,.,.alkeetna Mountains,Mt. Hayes,and Gulkana topographic maps. The drainage network,lak,;s,glaCiers,morain- al areas,channel bars along the streams.and swampy areas on part of the Healy map are shown in Figure 8 Since the a"rldl photographs used to make the topographic maps were taken from 1947 to 1957.many of the differences in the stream chanl1els,especia!l y those fJroxlmate to the glacial terminus.are a result of natural changes that have occurred between 1957 and 1Q7&.These differences are 1I0t necessarily due to differences In the resolution of the aerial photographs and the lilndsat imagery. The number of streams shown on the Healy topographic map (Fig.8)is much greater than I mapped from landsat imagery (Fig.7).I was un- able to see some of the small tributaries (\n the Imagery because of the landsat MSS pixel res'o- lution,58 x 70 m. The small streams are frequently narrower than this minimum detectable size,The light re- flected from (;w small streams and other fea- tures smaller than this area is integra,tf'd into one brightness value for the whole area.(omequenl- Iy,small streams.features a'ld objects are fre- quently not recorded as distinct patterns on the Landsat imagery but appear as part of the sur- rounding bedrock.sediment.talus,or vegeta- tion. ~~---~....-- Many of the small streams are Shallow.Bot- tom reflectIon of solar radiation from the bed of these small streams can be great.The amcunt of reflected radiation the landsat MSS receives from the stream water can be small compared to that received from the bottom.As a result,the scanner "sees"the stream in the mountainous areas as similar to the surrounding rocks.In low- land areas,this stream may look like one with high suspended sediment concentrations. Generally,most of the larger streams in the basin were visible on the imagery.The Healy topographic map and comparable Landsat maps show this.However,the streams north of Big lake (1,Fig.8)and southeast of Butte Lake (2) are art exception.There is a major difference be- tween the landsat map and the Healy map.in- spection of this area in Figure 4d indicates that the drainage network is not very apparent on this landsat image. The landsat imagery was useful in mapping the large-scale drainage network of the basin;it was insufficient for defining the myriad of small- scale drainage features. Lakes I compared the distribution of Jakes mapped from the Landsat imagery to that on the NASA aerial photographs and the Healy topographic map NASA photograph 16-054 (Fig.9)shows the lakes in the Big lake (1)area of the baSin.Most of the lakes shown can also be seen on the land- sat EDIES image [Figs 3 and 4d)NASA photo- graph l&{)&O (Fig.5)shows the area around the confluence of the Maclaren and Susitna rivers. Many of the lakes are so small that their shape could 'lot be mapped accurately but are easily observed on the landsat scene Frequently,the shape of the lakes is not as well-defined on thc landsat Image as on the NASA photographs be- cause of the difference in resolution between the photographs and the imagery. The lake distribution between the outwash plain (1,Fig.10)of the West Fork Glacier and Butte Lake (2)is apparent on NASA photograph 19{)35 and the band 7 landsat EDIES image (Fig. 4dl.The lakes which appear on these photo- graphs are more comparable to each other than to those mapped on the Healy topographic map. There are many more lakes present than shown on the topographic m~p.The NASA photographs and Landsat imagery show present conditions more accurately than the existing map. The Us.Geological Survey generally does not 14 .....,..-.-.......~...,.,__....._.._............--,__1-· ~--.---.--_.--_.~.'.....··.··1 >'.'~'1;.ci:w"~~.~. -':-;;":-~~~?:!-'~""~~~"... ..~...,..~~_,_---:.-.'~_-..-..,;...--....-.......:J!'•.".._. - .:....,. ._~.:r..~...e,~".. ;..-!.-1 ;--..... ~.~_r.E:. "~ ---._" // ).-"-<--'-'/,~, ./~A~••"'_.~\_._,.j~~A":--"'---/J,./'.--::J'.-\."-,,.~ ••I\.'-..........-...,,~...,~:-';,\\,\~"'- ((\\~,_........-.:..-" I \~'r...J,_.- -----/-'~t-_ Figure 8.Drainage network,lakes,glaciers,moramal areas,channel bars.and swampy areas on the USGS Healy topographic map.scale 1:250,000;Big Lake (1)and Butte Lake (2). ~ i include lakes smaller than approximately 222 m in diameter on their 1:250,000 topographic maps Experl.,nce has shown that lakes smaller than this cannot be adequately drawn and tinted'. landsat imagery.therefore.can be useful in revising maps of lake distribution.This landsat- derived map would in many cases be more de- tailed than presently available maps of equiva- lent scale. I determined the smallest lake visible on the landsat imagery by comparing the lakes on the landsat EDIES color composite and the band 7 EDIES transparency with those on the anginal NASA color infrared prints.The lake (3)in Figure 1.1 was only faintly visible on the landsat EDIES transparency as an indistinct smudge-not as a lake.Consequently.I did not map thi~lake ..hill' preparing the landsat-derived map bf the Idke 'Iohn ZYd,k.Ch,Pf,MAp ldlt,nK S..,l'on U S Ct'OIO~"d: Sur.-l"Y,Dt-'nvt"r.Co~o'ddo (pt'r~onltl <ommunl(.,tlon 1974) distribution Thi,lake is also not shown on the uses 1 :250.000 scale Talkeetna Mountains topographic map. The apprmimate diameter and surficial ar€J of lake 3 in Figure 11 are 50 m and 2000 m'. respectively.and the lake is only marginally vi,i- ble on the landsiit imagery.The dpproximate di- dmeter and area of lake 4 are 100 m and 8000 m',respectively;this lake is clearly viSible (fig. 4d),and was mdpped (Fig.7).Therefore.the smallest lake clearly viSible on the EDIES imag- ery would hdve a diameter of approximately 100 m and a surficial area of approximately 8000 m'. roughly equivalent to two landsat pixels.Each landsat pixel is 70 x 58 m or 4060 m'. McKim et al.(1972)reported that most water bodies of about 152 m in diameter or approxi- mately 18,000 m'in area are apparent on stand- ard,non-enhanced landsat Imagery.They re- ported that the standard Imagery generally does not supply information suitable fGr observing water bodies of less than 24.000 m' 1S --.__._._.._0_..__•• '--_.-...-----....".--.---.-_.,.I..............~I 5·:"'.$.1'i'Jl~;~~·--:-.- ".--.-.--.-"-_._...._----_.-----_._--...._it.,..1It I IH 'OOO'09L:L 'd{£':J~:tlJF U()I~~IW V'i\'N MUJJnp Li61 '~/lI{81 uo U';'1!'i 'pal£'SUlpunOJJn~pu£'(L)<1'1£'1 S/8 '6 dJnSJJ 1''';'',--c;.". ~- I ", 1r ! .~. '000'091:1 a/I?Js :t-9[UO!SS!W VSVN Supnp LL61 A./n/6l uo UCI'tPJ '(lJ a'lP1 ClJjng pup 1;ml'/9 't10J IsaM 10 (Ll UII?/d ~sPMJno a41 uaa .....Jaq eCl1V '01 amS!J "··'"-"·"""-·".·-"P''""-''"~'-~~-'--''--'------_~,..,._•.~__~,.......",,,...,_.",._,,,,.,'".._~_.....,'",.._,..,.,,,~....._'..,....._ ..... .....,. -...-....:,!-~...:' -.,~tI .., <. FigurE'II Area near the cO'1f1uence of the 5u~ltna 111 and Tyone 121 Rivers;la/...e J is mdrginJlly I'is/ble on the Landsat EDIES Image,Id/...e -1 is clear;ta/...en on 28 July 1'J77 during NASA mission J64;scale.1:160.0<JIJ. Cooper et 011.(1975)reported that,With digital processing techniques,the ~omputer compat- Iblp tapes (CCT)standard iMage data can show a circular lake WIth a m:nimum diameter of 148 m or'17,200 m'in "rea.Graybeal et al.(1974) reported thilt water bodies as small a;;8000 m' can be Identified occasionally on the:CCT data for standard imagery.The CCT's for standard im- ages contam all the landsat radiometric do1ta ,1S acqUired from the satellites Bands 4,';and & have 128 discernible levels of ro1diant ener~y; band 7 has 04 levels.These compare to 1&levels shown on standard landsat images. The improved E01 ES imagery with &4 levels of radlo1nt energy shows lakes of appro~imately the same size as can be delineated from standard image CCT data.If all the enhanced image data on CCl's used to produce EDIES images were analyzed.delineation of water bodies smaller than 8000 m'might be possible. The following figures are shown for additional compamons between the Landsat scene and the 18 t_~.;...._<._".:".,;.~_R ~.;u;o,"~..t- Figure 12.Area between Maclaren River (1 ]and Dickey Lilk!!12l in northeastern part of basin;taken on 29 luly 1977 during NASA mission 3M.scale,T:160,OOO. NASA photographs:Figure 11,NASA photograpt> 16-Q36;Figure 12.NASA photograph 19{)58.and Figure 13,NASA photograph 19{)56. Glaciers and snowfields The Landsat EDIES ,mage showed more snow- fields than I mapped since some of the fields ap- peared as specks too small to draw. The color composite EDIES image (Fig.3) shows the difference between Ice and snow and the surrounding terrain better than the black and white indiVidual bands (F'g.4a-dJ of thE'EDIES 19 image;ther2fore.it is considered better for map- ping the glaCiers and snowfields.The vegetation depicted bv red tones and the bedrock in various shades of gray on the color composite contrast- ed well with the blue ice and white snow.Differ- entiation of these features WilS generally easy. Differentiation of snowfields and some small glaciers was difficult because portions of the glaciers are snow covered.However,I did not at- tempt to categorize the glaciers and snowfields based on size. '-=----...-_..._--, "_.'--..'-----'-,--""--,,...-.•..:>-- ............I::W.>"tt'l~.,:..:.:.~.... ~'..·-·_.~w_.__-...........~,_....:...........,.~..~..--.~~....__........__...._"'"..__......._'-'-_ ... ."_.~,~,,~,.,~,.,,.~._.._-.~_.._._.•.__.__.'.,.__•_.·_···._H.•.__.,__·..·••_ I separated the blue ice and snow·covered portions of the glaciers from the dirty ice zone at the glacial terminus.A gap between the glaciers [red)and the outwash plains (blue)below the gla- ciers on the south side of the Alaska Range can be seen in Figure 7. The largest glaciers in the Upper Susitna RivN Basin occur in the Alaska Range.From WE'st to east.they are the West Fork,Su,itna,East Fork. Maclaren,and Eureka Glaciers.These glaciers are the primary sources of meltwater and glacial sediment for the Susitna River. 20 Smaller glaciers and snowfields occur in the Talkeetna Mountains.Clearwater Mountains. and mountains around Tsusena Creek on the northwest border of the basin.The T alkE'etna glacier.and dowfields are the ,ourcc>of three Susitna Rivcr tributaries.Kosina Creek,B!ack River.and Oshetna River.The glaciers and snowfields in the Clearwater Mountains are the third large'!in size.while those neM Tsusena Creek ,HE'thE'fourth. V"II"v gl,ICIl'rS <!rt'con't"ntly moving down- slop,'.tr,tnsporling l'rod,'u dt'brls to their termoni ~.'1i~oI;,ji(.~1~~·r·._'.~..:J,.~.I!J'~~·T.~,.,.;..._.._-..---...........~~~~:"",~.;.~'7..l.'+'.-t~J1""....~.;c: •~,.';""~'""_.'~'·......-__~_....,"......-...···_..e •••-·__;~""-'__""'_"'·-""'''''''>'''__'''''i''''''''__~_.,_ Figure 14.Terminus of the West Fork Glacier (4),exposed ice (2),meltwater stream~Il},debris at terminus (1), surface water (5),Nenana Glacier (6);taken on 29 July 1977 during NASA mission ]64;scale 1.160J)()(). where the d"bris is deposited.The terminal zone of a glaCier is usually composed of poorly sorted sediment overlying ablatmg glacier ice.Uecausc' the zone is dynamic,1 compared the l<lnd.~,lt ·F DI ES image with NAS.o\photographs acquired a year later rather than comparing I It to topo- graphic maps.I The distribution and large-scale ~eldtlonshlps of debris (1,Fig.HI,exposed ice (2),dnd melt- water ~treams 0)at tne termmus of West fork Glacier (4)Me similar on lhe landsat EDIES Im- 21 ,1gl'(rig \)and NASA p.hotogr'lph l'}-{XJI\(Fog 14).Surf.u ('w,lter (5)on the surtace of tho:'I('r- minus IS aho ,lpparpnt on both.howt'ver.sn1<lll- sc,lle roughness"appdrent onlv on the NASA photogrdph The I,ll"r,d ,1Od medidl moraines .lrp wt'li de- flnc'd 1 h{'!r p,l!terns are ('vlde;]t on the lands,11 linage and NASA photogr<lphs The p,lllerns "p- Ihuenl on tIl<'I.and',ll ~DI~S Image (Fig.1)and NASA photow,lphs l'H/OII (fig 14),19~112 (Fig 151,<lnd l'H110 (fig 16)show th,s (omparlson. .....-.:......."F:...,.--:s..~~.. _••"_~,•••__,_.••,__~.~,,_.__..,.__••_"___....'"'k~_ 1'J77 dUring NI\5A mission 36-1;scale,U6U,()()O_ ~1 ~ /' ;' ~. \-"y~4~ :~ __.J..'} J , Conclusions L,lIHJ,.11 II11,l~('ry pro,',d.,d ",>,tul lfliorl1"lIllll' for d.'lme,lllllg th£'mdl0r dr,lIo,l!:<'pdtt.-rO'_t!lt' (II,trlhutlon 01 I,lk",,lncl gl<1lI<'"or '"o\\llt'ld" m,lIlY g('ologir t,',HuH",It lht·l"rOlll1'oi tht' IMgt'gl,\(It'r"dnd rt,flt'l t'Vlt"(hlt ..rt'nll"01 I"kt",lI1d 'Iv .."AI,o,Il1dny 'm.tll I,lk.."11111 ,h(,~\n on .lV.III.11l1 ..1 2'iO,OOO topol\r.,phll m,lp' \\,'rt't'\!llt-ot 00 lilt'1 2S0,()()O L,lI1d,at Illldg.'ry JIll'1Ill,I!-:('rv dill not ,how tht'I.lk.t"m~(h '1ll,III,'r th.lIl ilOilO Ill'III MI',l,\om ..oi tht' ,trt'drn,,rn,lll ..r th.lI'lht'r..,olutloll of thl'mult,- ,pt'(tr,t!".lIl1lt'r [70,'ill 111),or d d"tm(t ,hort'IIIII'lor '"Hllt'of the ,111.1/1 Idk .., 22 j, • I '=~~.-.-"i'O'''''''''::U:'''-~.!::-~-,-.---.----...----"I/"_.JtIl...............",••>#T'A"i'¥.q.·...:~.:----- -. • _4~._..........,......,.._______________c"••_,,_'_ Figure 16,Terminus of rhe Susitna Glacier (1);taken on 29 July 1977 during NASA mission 364;scale, 1:160,000. landsat imagery would be a useful 1001 for making initial large-scale maps and upddtlng the maps showing river channel configuration and location,mid-channel bars and islands.locations of river Icings,lakE'distrtbution,10cdtlOn dnd features of the glacier terminus,changes in 23 medial <Jnd latt'ral glaCial moraines.and changes in riVE'[and lake sl'chment concentrations. ~:.,~r;~...~;';~~~'~;;.2B:·,,, '---_._.-----,.,-----._-,.-_..- i J J / PART II.USE OF LANDSAT IMAGERY IN MAPPING AND EVALUATING GEOLOGIC LINEAMENTS AND POSSIBLE FAULTS. Carolyn /.Merry Objective The primary objective of this part of the pro- ject was to prepare a lineament map of the Up- per Susitna River Basin,including a 100-km radius of the proposed Devil Canyon and Watana dam sites. Geologic structure· Three joint sets,one well-<!eveloped and two poorly developed,occur in the Devil Canyon Dam site Mea.The strike of the well-<!eveloped joint set varies from N 45°W to N 1D O W and averages N 25°W.The dip ranges from vertical to 75°E and averages BOoE.Average spacing of the joints is 12 to 1.5 m with local variations of 5 cm to as much as 4.6 m. The two poorly developed joint sets consist of a tight set striking piuallel or subparallel to the bedding,but dipping generally north.and an eastward-striking.r.early hOrizontal set.The forst set has a spacIng of 76 cm 1046 In and the se- cond set has a spacing from 7.6 cm to 9.1 m.The loints in the second set are tight,dipping from 15°N to 15°S.wi~h the dip more commonly tJ.:-- ing horilontal. Well-<!eve!oped shear lo,'es striking N 25°W and dipping BOoE,spaced from 15 to 244 m.oc- cur in the bedrock of Devil Canyon.The shear lones appear to have developed parallel to or along the same trend of the well·develuped loint lone.The jOlOt lone is probably older than the shear lones. The dominant ",eologic structures at the Watana dam site are fractures which slri'-!"N 40-&O O W and dip to the northeast from 70°to vertical.·• I I ·Sf-ctlOn b...tc,pd on d fflport bv Kach,ldoOrlclll {1"U-I} .."I K SO(JE"r.AlclC,ld Dl\trl{t.Corp~ot EnKlnE"~Jr,.pe,"ondl communICatIon (1979' 24 Methods Cloud-fr!"e early winter scenes were selected for the lineament mappin",.The conditions 01 light snow cover and low sun angle accentuatf'rl lineaments.The four Landsat-1 MSS band 7 1m· ages which were used in the photomosaic were obtained on 2 and 4 Novemb!"r 1972 (NASA scene ID numbers:1102-20450,11 02-20452, 1104-20'563 and 1104-20565) The site location map (Fig.17)shows the loca- tion of the Devl!Canyon and Watana dam sites, a 1DO-km radius Mound each dam site,the Susit· na River basin bou~dary,and selected signifi. cant places DefiOitlons of selected geologic terms used in interpreting the maps are con- tained in the Glossary. Results Geologic lineaments A lineament map was prepared for the Upper Susitna River Basin from the Landsat black and white photomosaic at an original scale of 1 :250.000 (Fig.1 il).There are many more line- aments evident on the Landsat photomosaic than shown on Figure 18.Only those lineaments related to reported tectonics were mapped. Therefor~.this lineament map differs from pre- vious lineamf'nt maps for the area which usually included all lineaments.Lir.!"aments aligned in the NE-SW i.nd NNW-ccE directions were in- cludt.d rn Fig H!"18.lineament~in the E-W directl".~"."c,e not mapped. Three major periods of deformation are recog- niled in the Talkeetna Mountains.a maJor por· tion of the Upper Susitna River Basin.These in- clude:1)a period of intense metamorphism.olu- tor,ism and uplifting in th~late Early 10 Middle lurassic.the plutonic phase of which persisted into Late Jurassic;2)a Middle to Late Cretaceous alpine-type orogeny.the most intense and im- portant of the three;and 3)a period of normal and high-angle reverse faulting and minor folding in the Middle Tertiary,possibly extend- ing into the Quaternary (Csejtey et a!.1976). There is a dominant NE-SW striking structural trend in the Talkeetna Mountains-Alaska Range ~,~~_...--...-.....__... l .__..__,__...~__,,.~~'\~'".~5··.~W~·~...:.""'i·~;~ as &((126 a 044*.;;:£;q.&?CS;:C\ , 1 ! ~ld~"~ ~51 s:UVc!5IH. ;I--=-c.. .---.--...---~'-.-- '~~~~.:~-:":~~~~~~~'.;\)~~. ~,"<•.._------~-----"-._- .."_._----- -~cl,6 0f/"ll ll''I fl U[';Y1'1 '/.1 tIl'W'1'llJ .I',r'::hl ,H ;.I 'I;;L'lIJI\rI 'i U"')(I'I h .I .1)11111 J ,l.lPI\U'MUJlIl II Ilnrl l"U'U Y 'Ir"'lrlllj'il'll = p.J )Ut)).1J':)l~'\'\ "\Iuddr "n"rJ "., ":~':'~.:,~~~'"f~-;1"'~;>;~''';.' ..-.'. -_..-------___0' ,...,......•...,------------'~---~--_..--.--'....'--"''''----"'-. .~ complex as a result of the Cretaceous orogeny (Csejtey et a!.1978,Gedney and Shapiro 1975j.It was also found that several strong lineaments in- tersect the Denali fault from the southwest (Ged- ney and Shapiro 1975).One lineament follows the southeast margin of the Alaska Range and in- tersects the Denali fault near Windy.A second lineament parallels this about 60 km to the east and intersects the Denali fault in the depression occupied by the Susitna Glacier. The secondary set of lineaments in the study area strikes in a NNW-SSE direction.The prin- cipal examples are the valleys of the upper Talkeetna ~iver and the Sheep River.These line- aments are considered to be elements of the same fracture system and,therefore,subject to the same level of seismicity (Gedney and Shapiro 1975). The E-W lineaments do not occur often, which tends to cast dou:Jt on the fact that the Susitna River course is fault-controlled (Gedney and Shapiro 1975). Known faults The regional faults of the area were mapped on the black and white Landsat photomosaic (fig 19) The Denali ~ault is located less than 80 km north of the Devil Canyon and Watana dam sites,and thl'Castle Mountain fault is located to the south These faults have been fully docu- mented in the field and are known to be large- scale right·ldteral strike-slip faults (Gedney and ShapirO 1975).The Dpnali fault shows evidence of a 3-cmlyr average slip rate durin~the Holo- cene and could sustain a m,l~nitude"80 event on the Richter scale (L ..hr and Kachadoorian un- dated,Gedney and Shapiro 1975)The Denali fault was formed by renewed northwestward plate motion i:l the northern Pacific plate since mid-Tertiary time (Richter and lanes 1973). A fault had been proposed by Gedney and Shapiro (1975)starting at the Susitna Glacier on thp north to south l;of the Talkeetna River.How- ever,reconnaissance work in the Talkeetna Mountains quadrangl\!during the summer 197i showed no evidence of this.·'In fact,evidence for recent fault movements was not found near ·St't"'d..·fln.llon of PdrthqUdl..mdJ.:nt'ud~In Ih,p C/oJ~c)lY M.lKOItud~In lhl~rt"'pof't wall be"tC~prt'\\'t"d In f,prm5 of thi" Richter Hdl{'"1 t-w A.1od.llfOd MendH,'rdl~I~u,t'd 10 de\(nbe pdrthqudke Int~n"IIY •"8.C''''II~y.II.U S Gt"OIO~lCdl Surv~y.person.I (om· munl(dll'>n 1197q) 25 the Susitna River within the Talkeetna Moun- tains quadrangle (Csejty et al.1978j. A major structural boundary is a line of faults that extends northeast within the Talkeetna Mountains quadrangle area.The most promi- nent fault of this set is called the Talkeetna thrust of Cretaceous age (Csejtey et al.1978). The Talkeetna thrust has placed Paleozoic,Tri- assic and,locally,Jurassic rocks over Cretace- ous sedimentary rocks.Another Cretaceous fea- ture is an intense shear zone,which is locally as much as 25 km wide,southeast of the Talkeetna thrust (Cseitey et al.1978). There are two poorly exposed normal faults as a result of a CenozoIc deformation ir the Chulit- na River valley;other Cenozoic faults have not been found within the Talkeetna Mountains quadrangle (Csejtey et al.1978). There is an apparent graben formed by the western flanks of the Talkeetna and Chugach Ranges and the eastern flank of the Alaska Range.Cretaceous to Recent faulting and shear- ing has occurred in this area (Lahr and Kacha- doorian undated). Activity of other faults in the Upper Susitna River Basin is uncertain and the shal:ow seismic- ity data are too scattered to determine any asso- ciation with individual faults.Shorter faults and shear zonps trenoJmg at high angle to the north- east structurai trend have been identified in cer- tain ma~ped parts of the Upper Susitna River 8aslO,and it has been assumed that similar structures along this trend may be common (Gedney and Shapirn 1975).Evidence of recent faulting has not been reported.possibly because of the lack of mapping (Gedney and Shapiro 1975). Cseijtey et "I.(1978)present a detailed dis<.....s- sian of the geologic units and ~aults found in the Talkeetna Mountains area. Epicenters The proposed Devil Canyon reservoir area is located in the tectonic zone which extends along the entire margin ofthe Pacific plate (Fig. 20).The Pacific plate is moving northwestward with respect to the North American plate (Lahr and Kachadoorian undated).Three types of seis- micity events are associated with plate tectonic movement:1)earthquakes,such as the 1964 Alaskan earthquake with a Richter magnitude of 8.3 to 8.75.that occur on the surface of contact between the Pacific plate and the North Amer- ican plate,2)earthquakes that occur in the ---."...----.---'.r ._-- ~';-._--. ~.~,_•••.•_.,.0,.........,_.•~_.......,~_...._._~...~__~~.'-'.~.. ............•...,,-_"_..~_~-,--_.~.__---------_. ___T,.n,currf!nl t.utt ~Tr.n'form flu)1 ",...,."..lid •• ....,."Tr~nch .~::;:~Ji Vole."lc .r( i eooplate 1100= ~ ..0' ....~--A.J .,.,~/~-~....'f;J-.7~., 1000 , Volclno ThrUIl foull Paei fie 1C1\.~It' \ plate eXPlAN'&.T10N -- \eO• .,.t1 o 500e=r'Fa &i Figure 20.Map of northwestern North America showing maior tectonic feature~ (after Richter and Matson 1977,Tobin and Sykes 1968). North American plate in response to stresses produced by interaction with (he Pacific plate. and 3)earthquakes that occur in the Benioff sei.;· mic zone*of the Pacific plate.which is being thrust below Alaska. The oceanic crust of the Pacific plate is ac- tively underthrusting the North Ameridal"plate along the Aleutian volcanic arc (Fig.20)(Isacks 's..definilion ,n Closs.Jry. et al.1968.McKenzie and Parker 1967.Plafker 1969.Richter and Matson 1971).Southern Alaska between the eastern limit (,f underthrusting along the Aleu(iar,.-.rc (at about 145°Wj and the southeast part of the Denali fault system is largely uncoupled from the North Am::!rican plate and moving with the Pacific plate (Richter and Matson 1971). The epicenter map prepared for the Upper Susltna River Basin S!10WS the location of epi- centers from 1 March 1975 to 14 Octol)er 1976 26 -l.....--__.__•. j'--- '.~~~~~~[f'~~b::.--- t ...~."_...J.__:__..........----~..---.--~_"'_......._........__...._._.-..,-..t;:',.;~..-.-.t'"",~":.~__""""",,_,,,~,.~~~.•.A.'"L~.:'}•..l'..:J.;,;t;,.:....':'".::::i.a-.-r.-"__~~'•.~:"':"'-':.l_~~";"..! ,!!g J<I \f;-!l'U/lms Jaddn '/Ja/u,Jj/d l 1j'<lJIIl!1/ £ •..'OOl-OOI • •'I"bb-O~ • •,bbt-~l •..~b'tl-O ..t'!b'7-0 l!u~r .... o =~ ,'Of'-_',..-~r~'-"'--J", ~.-.__.---.,.,..---.-------- ,i ~_.......~~'.-...s.--~~-,.a:·~:..'¥::-"."'.r-..__·.~~- r f "~. ~:q for a l00-km radius of each of the proposei:l dam sites (Fig.21).The epicenter locations were ob- tained from the earthquake data file prepared by the National Ceophysical and Solar-Terres- trial Data Center.Environmental Data Service. National Oceanic and Atmospheric Administra- tion.In addition.other earthquakes located out- side the 1QO-km radius were plotted in F,gure 21 to provide a regional perspective of seismicity for the study area. The epicenter map (Fig.21)updates a previ- ously prepared seismicity map (lahr and Kacha- doorian undated).Earthquakes shallower than 50 km are not associated with the Benioff seis- mic lone.The epicenters at a 33-km depth usu- ally Jack depth control and may be deeper than 50 km.Seismicity in the region of the proposed reservoirs ranges in depth from less than 10 km to greater than 175 km (lahr and Kachadoorlan undated).Seismic activity deeper than 50 km is postulated to be associated with the Benioff lone of the underthrusting Pacific plate. Table 2 is a tabulatior.of the earthquakes which occurred within the 100-km radius of the Devil Canyon and Watana dam sites.These earthquaKes include those with a Richter magni- tude of 4.0 or g~eater occurring from March 1975 through Decemb~rt977.There were a total of 52 earthquakes of Richter magnitude;.4.0 which occurred during this time interval.''''~ost earth· quakes were recorded at Richter magnitudes between 4.1 and 4.9 at depths generally greater than 50 km.Thes~earthquakes are assocIated with the Benioff seismic zone of the PaCific plate.An earthquake I"Jith a Richter magnltOJde of 5.7 was recorded on 18 May 1975.The earth- quake occurred at a relatively deep depth (96 km)and is also associated with the Benioff seismic lone. The nearest ear.thquake to the Devil Canyon dam site with a Richter magnitude greater than 4.0 was recorded at a distance of 21 km.The magnitude of this earthquake was 49 on the Richter scale.The farthest earthquake within the 1QO-km radius area was recorded at a distance of 100 km with a 4.5 Richter magnitude.Both earth- Cluakes were the type associated with the Beni- off seismic lone. The nearest earthquake to the Watana dam site was recorded at a distance of 36 km with a 4.9 Richter magnitude.The farthest earthquake within the 100-km radius was recorded at 98 km with a 4.2 Richter magnitude.Again.both earth- quakes were the type associated with the Beni- off seismic lone. 27 "'WGAiB a .c.Jq,........'P -..- There were 62 earthquakes recorded with a local Richter magnitude less than 4.0 from March 1975 through December 1977.The closest earthquake to the Devil Canyon and Watana dam sites was recorded at distances of 16 km and 12 km.respectively,with a Richter magni- tude of 3.8. Earthquakes llccur mainly near Mt.McKinley (Fig.20).These earthquakes result as a direct response to the subduction of the North Pacific lithospheric plate (VanWormer et a!.1974).The seismicity is generally rather deep and poses no genuine hazard to any existing structures or set- tlements (Gedney and Shapiro 1975).Deeper earthquakes also occur along the subduction zone extending southward from Mt.McKinley, but these are unlikely to be large enough to cause extensive damage.Eastward of the Mt. McKinley area the seismicity is relatively shallow and confined generally to the upper part of the lithosphere [Gedney and Shapiro 1975). Conclusions A lineament map was prepared of the Upper Susitna River Basin using landsat photointer- pretation techniques.Also,maps were prepared. based on a review of the literature,of known faults and epicenter locations in the Upper Susit- na River Oasin. There IS a dominant NE-SW striking and se- condary NNW-SSE striking set of lineaments in this rel.:ion The dominant lineaments within the 100-km radius of the Devil Canyon and \Vat ana dam sites are associated with the following tec- tonic origins:1)lineaments associated with the Denali fault;2)lineaments associated with th~ zone of Cretaceous to Recent faulting and shear- ing;and 3)lineaments associated with and to the east of the Talkeetna thrust. The literature to date.field reconnaissance and epicenter activity indicate that recent fault activity has not occurred in the Devil Canyon and Watana dam site area. The epicenter map shows that 52 earthquakes of a Richter magnitude"4.0 occurred between March 1975 through December 1977 Most earthquakes were found to occur in the Mt. McKinley area.as a direct response to the sub- duction of the North Pacific lithospheric plate. The nearest reported earthquake found in this study ~o the Devil Canyon and Watana dam sites was at a distance of 16 km and 12 km,respec- tively,with a Richter magnitude of 38. .._..•._..~_._"._----_...._----~._._-----_._--"--_.."--.--_..__._._----- r f I Table 2.Compilation of earthquakes with a Richter magnitude ~4.0 fromIIMinch1975throughDecember1977withina100-km radius of the Devil Canyon and Watana dam sites. O"'anc,,Irom Lilrirud"Longilud"O"pth De\llJ Canyon \,Valana Oil'"tON)tOW)tkm)Mdgnitudp (kml Ikml 11 Mar 75 &31 148 6 56 41 42 37 18 Milr 75 b3.3 150b 129 46 62 115 19 Mar 75 62.8 g06 77 46 66 105 20 Mar 75 632 1507 130 49 8)119 20 Mar 75 &32 1492 75 4.5 4&5~ 2}Mar 75 bll 151 0 130 46 90 126 24 Mar 75 612 1';08 III 44 84 119 2b Mar 75 630 lS05 92 42 b4 102 13 Apr 7S 613 149.7 %4b 62 8l 19 Apr 75 62.8 151 2 114 42 95 1]4 11 Apr 75 629 15U 116 45 100 1]9 lb May 75 b2.9 1499 68 43 .II 70 17 May 75 HI lS06 123 40 7'l Ill. 18 May 75 &lO 150 1 96 57 44 61 :0 May 7S 629 150 1 1 II 4.6 42 BO 19 May 75 612 1 SO.l 54 40 5b 87 11 'un 75 b2.1 1495 41 45 81 95 22 'un 75 610 1500 b4 41 Jb 7l 14 lun 75 &19 1506 10.1 46 7&115 11 lui 75 b31 ISO 7 143 4.b 7&113 8 Aug 75 b3.1 1505 124 4b 74 107 10 Aug 75 6l 2 150 4 119 46 bll 102 17 5ep 7S bl4 U9.7 101 44 1,7 87 29 Sep 75 b28 151 1 105 41 '12 111 29 Sep 75 b34 150 }79 41 79 108 J():;"p 75 b32 1504 128 47 70 104 11 Oct 75 b30 1508 109 41 /7 115 15 Oct 75 blJ 150 8 114 41 90 124 25 Oct 75 bJ4 1499 60 41 74 '17 10 Dec 75 624 1500 ~b 41 4'1 78 19 [kc 75 b24 14/1 b 33 42 1>5 52 1'1 Feb 7&!.o3 1 14')6 91 44 \7 b2 11 M.u 7b b35 1487 n 42 81 7b 26 Milr 76 636 147b 1I 42 121 96 11 lui 76 b32 1507 120 47 62 117 21 Aug 76 b29 1509 119 41 81 120 17 Aug 7&b2.3 1494 51 4 I 59 74 16 Sep 76 62.9 1S(l }97 4.l ~1 91 19 Sep 7&b3.0 151 2 lJ2 45 %1l~ 18 Oct 76 bll 1507 12b 49 1\9 122 24 Oct 7f>62.b 1491 75 49 21 Jb 3 Nov 76 6.1 1 1510 III 44 811 125 4 Dec 70 b}2 lSO.8 129 4.l 8b 122 lS 'an 77 b2.8 lS04 100 4 l 54 9l 5 Mar 77 bl2 1505 122 42 75 1011 20 Apr 77 62.11 151 0 114 45 llII 127 1 May 77 bll 1509 134 4.0 8'1 115 f>lun 77 62.2 1495 bO 4.1 74 119 2J Aug 77 b37 1494 12b 41 100 106 9 Sep 77 b22 1495 5'1 46 71 86 190077 b29 150b 102 50 bl 102 20 Nov 77 b2.4 1507 79 49 81 lib; i i I I 28 I I i 1iI~ t '·1 ~ t I "~~-...,;~:!~~~~~.t~~bi;;;{fi:-t I':~---~"---_.-...,---_.,-_.,,---- ~-... r f f !, ~"_",__...,,_..-.....~.,...,......_......~.,,_r.~.• r f~ , PART III.USE OF LANDSAT IMAGERY IN MAPPING SURFICIAL MATERIALS SECTION A.LANDSAT MAPPING Harlan L.McKim Objective The objective of this part of the study was to prepare a surficial geology map of the Upper Su- sitna River Basin from a color composite of landsat imagery. This study was initiated to evaluate the utility of the Landsat data products for Corps of Engin- eers'soils and geology requirements.The surfi- cial geology map should provide information on the types of material in each unit,provide a large-scale map that can be used in selection of drilling sites,provide a basis for estimating tra:Jsportation cost of material to the dam site and serve as an existing data base for selection of further low-altitude photographic missions. It was assumed that the imagery could pro- vide an adequate amount of information in remote areas where ground truth data were not available or would be very costlv to obtain for the early planning stages of a project. General geology The status of geologic mapping in the Upper Susitna River Basin is shown in Table 3. Argillite,graywacke,metagraywacke and slate of probable Cretaceous age underlie the proposed Devil Canyon Dam site.The units are exposed along the Susitna River from a point about 24 km north of Talkeetna almost to the mouth of Tsusena Creek,and in scattered out- crops throughout the proposed reservoir area (Csejtey 1974,Lahr and Kachadoorian undated). This rock unit consists of hard,generally mas- sive,medium-to dark-gray metamorphosed fine- grained sediments that contain numerous string- ers and vugs of quartz (Kachadoorian 1974)Ma- jor structures in these rocks are a series of isoclinal folds striking to the northeast (Capps 1940). The bedrock at the Watana dam site consists of a crystalline (diorite)pluton intruded into 29 older Tertiary sediments of shales and argillites with some Tertiary volcanic flows.· Two diorite and granodiorite bodies of Late Cretaceous to Eurly Tertiary age,which arc similar to the Talkeetna Mountains batholithic complex,have been mapped within the southern half of the zone of metasedimentary rocks (Gedney and Shapiro 1975).Several irregular bodies of granite and granodiorite of Tertiary age have also been mapped along the western flank of this zone and an extensive area of these rocks occurs about 32 km to 64 km north of the Susitna River (Gedney and Shapiro 1975). Glacial moraine is the predominant surficial geology unit in this area (Kachadoorian 1974). Evidence from glacial striae,topographic maps and aerial photographs indicates that the glacier moved westward across the area (Kachadoorian 1974).Unconsolidated materials deposited by alluvial,glacial,swamp and lacustrine processes during the Pleistocene and Holocene times oc- cur throughout the region (Gedney and Shapiro 1975). Methods An EDIES color compo;ite at a scale of 1,250,000 was used as the photo data base for the surficial geology mapping.The color compo- site was purchased from EROS Data Center, Sioux Falls,South Dakota,for $1000.An acetate overlay was used for the mapping exercise.Ade- quate ground truth information was not avail- able,but some exploratory soil survey i'lforma- tion within or in the proximity of one area was availa~le (Reiger et al.1979).This exploratory soil survey was placed over the photom<,saic as shown in Figure 22. The mapping units selected Wf're differenti- ated by geomorphic position,infened.slope, vegetative patterns and lake del1sity.The tone and texture changes on the imagery indicated that these parameters,ev'O!n though not implying genetic differences,could be separated.Be- cause the reso:ution of the Landsat imagery is about 58 x 70 m,objects smaller than th;s size 'f K.SOpef.Ala.ka O"trict,Corp.cf Eng'ne<!rs,per"lnal C'lmmunlCa!,on (1979). Ir !Table l.Previous geologic mapping in the Upper Susitna Riv«Basin,Alaska. Sourc'!ArN mapped SR.Capps (19-40)Talh~tna Mountains B C~ltey (19741 Talk~~tna Mounta ..u (Wal"n" l"ke area,(·4 Quadrangl~.A·S Quadrangle/11974/ 8.(~jtey ~t al.(1978/Talkeetna Mount"ins qu"d,,,ngle (1978) H M ae,kman (19741 Southeasl Quadranl of Alaska T.E-Smilh and 0 l.Turner (1974)Area north and weSI of 62°4Q'N/ 148°45'W.Including northeastern pari of the Talhelna Mountains quadrangle R G FortM.s et al [1974)Discussion of grochronology "nd tectonICS of abov~area R.I:achadoorian (1974)Dt!\'il Canyon dam site l.uhr and R.Kachadoorian Devil (anyon and Watana Res~r- (undaled/VOII areas H M.Be,kman et al 11977)Eastern part of southern Alaska ..........-' -----~-~---------.. coarSe--to fme-gralned depoSits occurr- Ing on moderate to steep 510pE"1ln mQlin- la.nous terrain and rollIOg uplanes thai ha,'~m.nor scatlered bedroc~e,~ure1 r~st"(ted to the uppermoSI slop'"and op5tlanes.bedrock ~iposures c..75~ und,fh:re-nt Idted allu\llal·glac lof (UVial depoSits assollated with &entll'to mod· erate backsloPE'.and fooufope POSIhons; fin ....to coarse-gllaned "lIuv'al fan,ter- race.stream and eol'an depoSl"t~de1'I\OPd 'rom rework'!d glaCial and allUVial depOSits.morainal deposils.till.and out· wash gr"vels and sand~,occurllng In part on moddled morainal topograph.,.and large alluvial lerrace~. Und I If erent'a ted f I uvi al·1 acUs tro n'! d'!pos,ts;fin ....to med'um-gralned Sdnd~ and slIts assocIated "'Ith modem and abandoned floodplaons and Iow-Iy,ng terraces,pOSSIbly including eohan Sdnd~ and s.llS;K'!nerally poorly dralfled. saml'as II"l'xcepI for ft'Wer lakM and not .as poorly drained. un\legetate-d moraines fl, fI, ag bc um Tones and texture plus the use of minimar stereo coverage aided ir.t!lis analYSIS,It was relatively easy to differentiate the band bc units,The dark grey colors in the mountainous 30 ifH,tu tM.drock and very co.;se bedrock colluvium pumaflly confined to steep slopes and mountaIn cr'!stl,nes;bedrock expos"r'!,~75". b Results Careful examination of the color composite resulted in the mapping of six surficial geology units (Fig.23).The descriptions of the units are as follows:I cannot be seen on the imagery unless they con- trast significantly from the surrounding terrain. An important a.~pect in determining th~num· ber of delineations to be made is the ~ime and cost involved in the study for the amc~nt of in- form~tion that can be obtained from the im- agery.The need for information from landsat imagery generaliy arises during preliminary in- vestigations where adeq\.iate ground truth is not available,A single landsat scene covers about 185 x 185 km and co~ts S8 for a 22.8-em print, The time involved in mapping the surficial geol- ogy on the landsat scene for this study was less than two weeks,Therefore.much geologic infor- mation in a remote area can be quickly and cost- effectively obtained. J, • I "\ -------------.~-.~__....m~......_l,,'__._......._ .. t t ~. fl-~ lp. r I !r~ ------~----- eo.3 2i an 510.&a 4 a;p LAMa is 4 ...5 lac;44 $.£j 1._:_& J,_ _""'·_"~'.,"..__e_.,_''-'_''__••__._.•_ IQl Hislic Perl:clic (,y.lquepls."""'"le\el 10 ",lIin,;.claycy lEGE~,m I 11!.1If(·22.I '/llm.l/of\'\011 'LIn l'~m"p "I Ill<'("1 ~/I,'II1,1 ~I\,'r /l.,-III..·\I.I\~,llffOlI!R''.l!{'r ,'r ,1/it l"I'/2"lroll,ol1 rJf COIOrl'd 0\1',/,1,'"1101 .1«(( l'\,'1\\\I,,',.,Oil /1.1 VI'pllu(ogr.lph !Jpc,JU,e (1'mdl ,1"1IJ~,lg('I IUl Pe,\:elic ("umh,,,pl'.hilly 10 ,/,,('p.vrn I:rdvl'lIy,dnd ",u/:h mounldinou.I"nd 1U2 Pcr\:elic ('tumhrepl."nd Hislic PN~c1ic (,y"qucpls,hilly 10 .Iccp.very 1:,.nellv [....~hpic Crydquepls.""HIv Ic,,,I.,.lnd, \Olb Per\:e1i~(,ynrlhod•.hill,10 slcep.,,"V ~,."cll,.dnd Hi,tic PC1l:cliC (,~aqu"pls, nCdrly lev,,1 to rollin!:,I<>dm\' RM'Roul:h mounl.lim'/s 1,1Od SOl~PNl;dic (lI'orllwds.hillv 10 ,Iecp.\NY l;'dwllY .100 rough mounldinous land IQ2 Hi\lic p"r~c1ic (r,.HjUepl •.ncarlv ,..,,,1 lu ,ollinl:.IOdmy SOl;p"q,dic (n'orlhod.dnd Histic Pet l:e1ic (r\.lQlIept"n"."ly Ie''''III ",lIin!:.'NY ~,.wdlv SOil Humic (r~orfh()ds.hillv 10 sl""p,,,,ty l:'d",lIy dnd Terrie (,y"h"m;,ls SO!(l Humic (n nrthods,hill~I",'eep.-ety ~,a,dly .",... V ~:.'~:.~.J.,,:ii..~~~;~·"_~~~" ~~....~.t:..-\}J(~~"'~~""'..:;..m-..',.............,-. ""'III!'IL-.,..~-..:,:~",'........~".__•,::t", .'.'--'1~J"".".'~Pj"...I I ••.'..:',~.,! •~6 I .~..\,"". ;I'.,,~. rT- --"----,---- .. .",'"1 1 •_;.;~•...?t ,0'"0,. 'A ,,"',IJ.....~~r......\··..1 J,._..,~' -IX.~':',.1111'0,1 4'\,.l ,)(lJp'''l :~"UHI,.lJ)lJ!"IUIIUUI pur ,...tl°I' doi'i'I'UI p.UJ~,un.)'flU'lUIU'Lunl\UnO)'!"PJ -V"'l '1'1'1"'',,,"''')'J,l\pill''I""!>'"l "1!""1 'I -IXI~_,~"Jt"H,h.,,.HUp,)\':....'UH .}(,.a.:l put",~('nl'"u,UJ,Hh'"'''II "I p.ll l~JI' -.lJ ~...~n'lu.h~',.lIUlhlq Ih'~.l""l'JUll~'" ~'"l '1.11,,"'PU"1<1o :ill!"'"pUl'IIlr''''. ~nou~t"IUn(nLi lI~~.,d')I~d.l.l"nl .11 "J.l1''''''lIO ~U!un'>.ln 'I!,,"ud.'p Jl.'lllll'J';'(-.lU~J UI _,..,U'O)HI .~.,,ru.11 l'.~\n,p·'litH",put"\"drJ'iiot'OI It'"u,rJuul p.lIPPOlU lIll p,tll 1I1 IIDlU ~"PUl'" pur 'I.l\("j~'l,'''''lIHI pill"'111\·"l'"U~·.lp If'UIl"'JnUI "I!'litut.1p 1PI \n\p'IHH'p.,U'l:1 V..',JO'M,,)J lUlU'p~l'~J.,P '1I'rolUt.'p Ul'~tn.l JUU' 'Wl'".'lJ,''.'l'·JJ.'1 ·U.',~"'\Illl"p.lUU'j';f·,·..Jl'Ol III -..lllq :"Jtl!J~'(Hl "dol'I'Hl~l"ll',Hlo,'"H't! .;l}rJ.'fHlIU HI "'IlU"~'11'"p.11"110~"'1',)!,ul1.1 p 1"""II"!:>r l:i '\r"nil"1'""'"1I,Il ,l"'1"1 t\;I,' 'l~ll "'I"PI''I I • aN:l~:ll ·p.lll~\·J~) '1 Jluu.l ,,"(""H"'~:"1"1>11\',pu.·..lI'"'''''' .lpnpul ,....w :...l n"u."':lu~'I-\o\CII pUt-·.;,u n·l(' -ponl'p.'UUPU,·tp·pur lU,lptHU 'II!"lhl"'~1 -(~l"'....'11'put"..put'"p.HJI'·J:\·U1n~p.HU ,,'-.llJ!, .'Ii nd ••p ,1U!Jl,nJ'"I-p'''\111'p.1''''!lu.U.lll !PU 11 I" 'lhHIU"Jp 'p'HHt 'lot"t OU pur ,.,,\r\hlYt..ll JU),d.ll'.'10 "".1Ull',"'I 1,1;1I'~lIIHI' I/I'W /"."m'"~I '1dl'j;1<lI<lttd ,1'1'(/(I<l ,nltl"II,>1,1 ll1l H"lilU "\1,,/,,1 \(..l)"ljcl/()",n lJl )/I"/I,,;i":-I I "'I')<'1 ,II"/'1,111 /)(/1'IJ,.;il'tlII 1I"lltll'/1110"1 Idl'llI ,,''1I'IJ.lII'W ll;i<l/'),l;i /1'1 111111\1,-,1111;;'I .-._---_.•._--- ~'-""""""~_"_"T""'~_"_~_"'.""""~_""""'_~..,.,_..."""'.......-,,_-.....-......-,.,.._....._ .. areas defined the b unit quite well,but the b unit was in part snow-covered.The be unit occurs .downslope from the b unit.The colors associ- ated with this delineation included lighter blue and some faint reddish tones.Due to the scale of the imagery.some of the upper tributaries of streams were included withi!"'this unit.The ag unit included the rolling and hummocky upland areas deflOed by the light red and pink colors on the imagery.The fl,unit occurred in the lower- lying areas adjacent to streams.The f/,areas were bluish red and contained large areas of open water.It was assumed that these areas would be PQorly drained.The f/1 unit was dark red and occurred in floodplains and side slope positions.When this unit was mapped adiacent to large rillers.it included not only sections of the floodplain but included some of the transI- tional zone between ag and f/,. The material size associated with each unit was estimated from knowledge gained from other studies where ground truth had been allail- able to test the relationship of material size to surficial geology un;ts (McKim and Merry 1975J. Since the map was prepared without the aid of ground truth only rough estimates of material size can be made. SECTION B.FIFlD EVALUATION Dantel E.lawson Objectives J examined the suriicial geology of selected field sItes in the Upper Susltoa River Basin to: 1 Evalua'a the aCGJracy 'lOd distribution of the mapping units used on the lands;lt~erilled surftcial materials map. 2.Dt:t p rmine the limitations of the interpreta- tion technique and landsat imagery for delineat- ing geologic matenals. J.Ellaluate the potential usefulness of landsat Imagery interpretation for environmental map- ping. Field investigations were done l!ldepender.~ly of McKim'~interpr~tations of the surficial materials from landsat imagery (Part "'AJ. Because the interpretation of land~at imagery is still developing and somewhat limited.such field investigations are neces~ar~to preCisely define the types of materials dnd thu~to devel- op a data base for interpreting that imagery. 31 Methods I reconnoitered the entire upper basin by heli- copter oller three days in the summer of 1978 to obtain an overall perspective of the basin geol- ogy.and then examined the surface and near- surface materials in detail at .ites located main- ly along the Denali Highway and Susitna River (Fig 23).These sites represent terrain covered by each mapping unit and major textural and color variations evident in the landsat image. High-altitude aenal photographs (scale 1 :&0,000 and 1 :130,OOOJ and ground traverses defined the geologic setting of each site.Wher- ever possible.I examined outcrops or dug a shal- low trench to determine the tf'xture.sorting.den- sity,·color and other physical properties of the unconsolidated sediments.The relationship of the deposit to landforms was also determined. ,extrapola!ed the information from t~e lim- ited site observations to other parts of the basin by referring to reports on the surfida!geology of parts of the basin.The surficial geology of the Upper Susitna River Basin is not well known. Mo~t of the older investigations (e.g_Moffit 1912,Capps 1940)were reconnaissance surveys conducted by the USGS.More recently.Kacha- doorian et al.(19541.Kachadoorian and Pewe (1955J.Kachadoorian (1974J and Cse,tey et al. (1978J mapped the surficial and ~rock geology of parts of the basin in more detail. I then compared the results of the field in- vestigations to the landsat-derived map of the surficial materials and attempted to reconcile diiferences betweer.the field data and the land- sat interpretation of the field sites.Ho~ever.the precise boundary locations of each mopping untt were not checked. Results During the aerial observations I determined that,in general.the exposed bedrock regions in the basin (map unit b,Fig.23J were accurately mapped but that the unconsolidated deposits were much more complex than the landsat- derived surficial materials map indicated Therefore.my field efforts concentrated on sites located primarily in the landsat-derived map units for unconsolidated deposits (Fig.23). These field observations also suggested that areas of till and related deposits of similar tex- ture and sorting were not sufficientlv distinctive on the landsat imagery to have been recognized and mapped This is surpming be<:ause they t.__..---......--..--._-,,·!~t~~~~:::j;.1'~·;;;":~~ ..~"..._.---'-""-'~-"-'----'--'----'-"'---'-'---_.---------------~.._--,,-~._._._._--, .. I cover large areas of the basin and are generally recognizable on low altitude aerial photographs Map unit bc ThE'small number of sites examined in the bc map unit contain mostly nun,erous bedrock out- crops and mainly coarse-grained deposits (Fig. 23).Most of the unconsolidated deposits in this umt are either tills and materials with sim.IM lex- ture or colluvial material.or talus from adja':ent mountain slopes.Boulders may protrude through the surf aces of these materials.The top- ography at the field sites in this umt range from steep slopes to rolling upland with a rough sur- face.The Landsat mapping umt description gen- erally represents the surficial mat('ria~s at these sites,but does not include a descrlplion of thl' morainal m~,erials. Map unir ag The deposits at field sites locatecl along tht' Susitna River near the proposed dam sites a"d along the Denali Highway In map unit ag indi- cate that the map unit description is inauuratl'. Deposits at 8 of the 10 sites consist mostly of fine-to coarse-grained till and olher sediments with similar texture and sorting (Fig 24J The,e sediments were sometimes observed inter- spersed with mainly glacioflUVial dE'POSlh Also, loess,a wind-blown silt deposit.was sometinlPs present as a thin «0.5-m)veneer.Allu\1.11 1,10 deposits are prl'sent below the muuths of narrow mountain valleys. The terrain of most sites is gently rolling to hummocky upland With a moderate to loc,dly steep slope.Well-developed latl'ral moraInes and kame terraces occur on slopes in several lo- cations.Boulders protruding through thl''lHtace of the tills locally roughen the surface. ComparISon of thl'geology ,It "X "tt',to th,\! shown on m,lps prepared by Ka(h,Hloori,1O pt ,d. (1954).Kachadoorian and Piwlo(l,)54)'lnd K,l(h,l- doonan (1974),"di('ate that the till ,Ind "nHldr dl'POSltS COVN much of thl'art',1 Ilhlppl'd ,I',lg Thl'se deposits Me intprspprsed w Ith 1ll,11Il1~' glaciol,lcustrine and glaCiolluv"l1 dppo,ih.111l'Y may be found In l'nd.latl'rdl 'Ind groulld mor,lIn," With smooth 10 rough ami rolling to lo(,lIly ,r,"·p surfdcPS. Map units fl,and fl, Both map units incorporate areas of complex geology.Glacial and fluvial depOSIts wilh super- imposed lacustrine and sumellmes eoli,ln dppos- 32 its covpr most areas (Fig.24)The topography v'U1e~These olrPas may be relallvely flat plol,ar surfaces with minor depreSSions,humrrocky areas With dramI'd and undralnf'd depressions, well·deflOed sinuous and Imear ridges separall'd by sw.II,·s and unorainpd oppreSSions,or d:scon- tlOUOUS rerract>s near abanc.;uned stream eh.lO- nels Rl'lIef 10 each casp is rl'lallwly luw,With the well-deflOpd ~Idgps shOWing maximum rt'lll'f of about .10 to 40 m.Thl'rl'!-:ional settlOg ut Ihe fIeld sItes is mdlnly broad vc'lIeys thill wpre rp- cently glaclatpd and now contain .Htivp ..trl'ams The Iypes of sedlmenls ol:,sl'rved 10 the ftl'ld IOclude lill and sedim!'nts of simlldr texturt'in thl'grouno,end and :.lter,ll moralOes;glacio- lacj;slrtnp dpposils in old 1.1;"1'pl,llnS and dl'- pmlts bpneath activp 100kes ,md swamps;iluvldl deposits in kamt>s,eskers.outwash plains,ter- races dnd old channels with bMs viSible on their surfaces;and complex mixtures of each of these (Fig 24)In some ('.lSI'S,well-developed.cldssical glaCIal landforms do not contain sed,m('nts nor- maJl\'found Within them Also,olher ridges and mounds that appear slmilM in lorm mdY,10 one instan,e,contain several UPposlls of ditfer('nt originS dISpersed Ihroughoul the same mound or ndge,.md in olh('rs contdln a singlp material dNlved from ont>prun"s.lMgt'areas wilh nu- mprOU5 lakes m.w be undl'rlaln mainly by de- PUSltS of outwash ,tre,lms.or by t,lI .mu m,ll,'- ndls of "mtl,H texture (eg hg 11 near 3 ,md 4), The 1.lke',SWdlllpS .md unurdlned dPIHl""Ons rr'sult pH'dulllln"ntl ...from \I,lgnatlon,buri.11 and ml'lllng of glacier 1('('Srmrl.H obwrv,ltlon,of the gl'olugy WI'H'madp by K.H hadoorldn l'l .,1 (1'):;4)ThE'distinctions bt>tw ...·n these different depOSIts WNI'not delineated by Ihl'Lanch,ll mapping. Map unit urn This unit,located at the mdrglnS of the Idrger glaCiers in thE'baSin,('onsists of supprglacial dpbns on stagn.!nt or ,1C tive glaCial ice.The dis- tribution of the dpbris appears accurately m.!pped,but thl'UOlt name,"moraine,"is mis- Il'adrnlo;.as it describes a landform.rath('r than genpral dt>bris or gla('ier Ice Discussion Imagery Interpretation The unconsolidated deposits in the Upper Sus.lna River L3dSln are "eddy more compl,'x .-,-.-.-..-._-..-.......~"'.-_-.._--_._---~ '---_.._--..·...~~·t~:-·~":'~.;..~-ut.; :I , f ~ J ·---__'·"_~'M _...."._"",_•.,••.,.""......,....,.,,••_;.............~__....,...........",.,..,_......~_..... Figure 24.Aerial photograph showing region near Denali Highway {I j and Clearwater Creek (2).The surficial materials at location 3 in map unit a~consist of till overlain by a thin cover of loess with minor amounts of glaciof/u\·ial and fluvial gravels and sands.I.t locatIon 4 in map unIt ag materials are also mainly till inter- spersed with sands and wavels.At locations 5,6 and 7 mapped as unit fl \deposits are complex.varying from largely till with a thin loess blanket (b),glaciofluvial sands and gravels in old stream channels and eskers interspersed with till (51.and till and glaciol/u\'i,}1 sands and gravels ;n morain..1 ridges with swales and kettles [7).Surficial deposits ilt location 8 in map unit Il,are similarly complex matenals in kames. eskers and end and ground moraines.Location 9 in milp unit II,consists of mostly till deposited as lateral and ground moraines.Loess may thinly cover some till and glaciofluvia:deposits throughout the region. Some geomorphic features evident on the photo include arcuate end and lateral moraines near and bela..... 15},abandoned stream channels below 14/and near (ll.and esker beJow (3)upon which the Denal;Highway is located,and lhe old r;ver channel occupied by an underSIzed Hream (Little Clearwater Creek.to).Photo taken on 29 luly '977 dunnf,i NASA mISSIOn 364;scale 1.160.UOU. 33 L '-------"'_,,--,_.__M'.,'.~:'..~\.i ~;~:~'i~~~·~;~·~~2~~.~ '"--"'"~'''-'''--"''~--'-''--~'~"''--'''''-''''''''''","_.".""""._-~".,.'~'------..--~....-.....---.,..,~-._-~'''''-.--,,-. , than those described by the mapping units of thE" L..nd~at·derived map.In part.this wa~expecled. however.because till and materials with simllal properties were not recognilable on Landsat im· agery,the imagery may bt'Inappropriate for mapping complex glacial dt'posits in thiS or similar regicos. Recent studies at active glacier margins (eg. Boulton 19&7.19b8,1970;Lawson 1979)indicate that the sedimentation processes in this environ- ment are very complex.Studies of Quaternary deposits (e.g Flint 19i1)have also shown re- gional complexities and interactions of the sedi· mentary processes and deposits of glacial and related peripheral sedimentary environments (e.g.fluvial.lacustrine).Knowledge of the pro- cesses ilnd dpposits of glacial environments may. be nepded to logically interpret these regions at the scale of Landsat imagery. Also.the deposits that were clp,uly misinter- preted were generally located in terrain with a maximum "'lief of )0 to bO m Relief of this mdg- nltude could not be differentiated on Landsat images,and this lack of resolution may account for the inability to distingUish between hum- mocky morames,pilted outwash plaim and flat ground mordine Bplter stereo coverage may help solve this problem 1 he Landsat images in areas mapped by Kach- adoorlan et al.(1954)dnd In areas where field sites weH'located did not show distinct color or textural variations that could be rplated directly to changt's 'n the tYPes of surfiCial materials pre-- Stonl.I suggest thdt this compamon bt'continued by earth SCientists in coo~ratlOn "With glacial geolog"ts to detNrTline If subtle variations are apparent on Land3at imagery. Mappin~;'nit nomenclature ThE'Landsat-derived mapping units probably should not include gfonetlc terms.as do ag,fl.,f1, and urn.but should only be descriptive as with b and be.ThiS wouid eliminate the errors in gen- etically Intl"rprpting tht'surficial material;The -mapping units for unconsolidated depOSits should Indude statements describing the sed,· mE'nt tl'\ture dnd possibly the interrelationships of the various units.Any genetic interpretations should be-~iven separately and include reasons for them.Thi~approach to dpscript;ve mapping umts does nol.however.solve the problem of in- terpreting the glacial history of thE'deposits ExamplE'S of dl'suiptlvP map units for the un- consolida tl,d cleposlts are. )4 all poorlv 10 well·,ort.-d sdnds Jnd Ilr ..el. /I ,.II,und,lf.-rpnlidled deVO>lI'of sorted.Ion ....10 mt"'drum'lS:(dmt-d ~dnd\dnd )Ilt~.mav be In· t("nrwf\(~d wit ....mdp umt r. und,fft"renlldtf"d.unsorh~d or poorly \orted. hnf""to (OdfW ·"fdlned ~f'dlml"nh.mav !...flO- ter ..pt"r....·d v.lEh sOftt"d c1t'po\lh of ~llt \c!nd or ~rd\'f'i Ie undlffelt>ntl.:Ht-d (omplpx of un\orh..d to wl!lI-~ortf'd flOp·to (oarst>·"rellned ,."(famerlts ~un"lt"'depo<;,.u drt"of insuffiCient dlmE""l~lons to map 'Iof'pdrdt~'y urn un\lt"N.t"tolt('d dt-brt...on ~td:gnd:nl or dCtr'tt" gldlter Ilt" The map units t and te would represent till and mixed deposits of different origins respectivelv. Additional data In the legend could include deSCriptions of the terrain (slope.relief)and landforms of each mapping unit.Genetic intE'r- pretations b.'lSed upon the descriptions of the sediment.terrain and lalldforms could also be discussed in the legend,but their inclusion as part of any text accompanying the map would be pre-fE'rr ..d. SECTION C.CO"'lCLUSIONS Camel E Lawson and Harlan L.McKim 1 Landsat imagery can be used to map surfi- cial ~eology on a regional basis in remote areas for prtoli;r,inary pld-nnallg purposes.It IS a cost- cHective way of obtdining general regional In- iormrltlon on the location of potential s,tes for construction materi ·\s 2.Most large areas of exposed bedrock were clearly distingUIshable from unconsolidated dl'-- posit~As e~pected.scaltered ur'-:-onsolidatl'd depo~lts surrounded by bedrock were 1;(>1 recog- nilI'd by Landsat Interpretation. 3.Arerls of unconsolidatt>d depo:,its in whi~;, ~mall bedrock outcrops·arE'common we-re not distinguished from areas without such O'Jtcrop •. Tht'ir presence can only be inierred whell I.:;q;er outcrops greater than approximately ~llx 70 n, (the resolution on Landsat Imagery)ere mixed and scattE'red among smaller ones. 4.field investigation showed t~dt the types and Origins of unconsolido\ted P'Ja!uia)s depos- ited In the 1-:1.1cial and perrglaCial environment could not be clearly d\dlnpd With the Landsat im,lJ.:erv.ThiS WdS particularly true tor art'as of , I ~~~---------~'-~-_.---- .. , } ~--------.~---..~_., I ..••.•.•_.~"""'~__• ,--- .--._--.-'-·p::)~~~~~~~J1~~~:0:. ~....Y~'~~"','._~L._.~".~...,-r•..oj._~_._._c "~-""'-'--''''''' .~.........."....1lll ........~-IIC~;,,;<...;-4·......•..J.:"'_~-___.....~~.{.:.......;.:.......,.•.'YO,,"'.-...~..~ ; (. f l ~.' I ! i, t L , ,~ I ( till and other sediments of similar texture and sorting which were mapped mainly as water-laid sediments. This inability to differentiate these unconsoli- dated deposits may result from: a.Indistinct differences in the landsat im- age that would show small variations in relief over short distances.For example,hummocky ground moraine may be indistinguishable from a pitted outwash plain. b.Sedimentation in the glacial environ- ment resulting from a complex interaction of processes.This compi\?xity often produces deposits of many origins that may be associated with one another and with more than one type of landform.For example,end moraines may con- sist mainly of till or glaciofluvial deposits,or a relatively featurelr >'errain underlain by till may be ;ntersperseci with ;errain bearing fea- tures indicative of lacustrine and eolian deposits. c.I ncomplete understanding of the past and present sedimentary environments of the region.Satellite and aircra~~imagery can be more accurately interpreted when adequate in- formation is available on the types of environ- ments present in the area. 5.Cround truth observation indicated that the mixed genetic mapping units used on the landsat map for unconsolidated materials should be avoided,because similar r:1aterlals may result from different processes.Only des- cnptive terms for the unconsolidated materials should be used.If necessary,these terms could be given with a separate or tentative interpreta- tion of their origins,including the baSIS for those interpretations.Descriptive units avoid the prob- lem of combining sediments of differe"t origins into incorrect and therefore misleading genetic mapping units. 35 ~i'..":~~I'r-.:.-~_-r",........~__..,.--_ ..........:~;.;.-..~ '''-~'''---'~''--~'''''-~-----...._'..,...-_."~-."........~"~.~-'-"-"._-"..._.,-~-....-,-~....---,........~-_.-_.------ I f I I f I f I" I rrr I irt I ItI,, t f I t f· t i f I LITERATURE CITED And~rson.OM..W.K.Crowdpr.loW.Catto.R.K.Haugen.T.l. Marlar.H.l.McKim and A.Petrone 11(73)An ERTS view 01 Alaska:Regional analy",of parth and water "'source'bas~on satellIte imagery CRREl Technical Report 241.50 p.AD7&S44219. Ander"'n.D M ..Hl.McKim.l W.Gatlo.R.K.Haugen.W K. Crowder.C ......Slaughter.and T.l Marlar(197S)Arct.c and 5ubarctlc environmental analyses utilizing ERTS·l imal'ery.Final ProlPcl Reporl submltt~to NASA. February. Belkman.H.M.(1974)Prel,mlOary geologic map of the soulheast quadrant of AI ..ka.U.S.Gcologlcal Survey MIScellaneous Field Studle'Map MF-612. Beikman.H.M..CD.Holloway.and E.M.MacKpYell.Ir. (1977)Generalized geologic map ollhe eastprn part of ,outhern Ala'ka.U.S.Geological Survey O~n File Map 77·1&9-B. Bilello.M.A (197S)A winter env"onmenta'data survPy of the dr"nage baSin of the Upppr Su'itna River.Alaska CRREl Intprnal Reporl 442 (unpucli,h~). Boulton.G.S (19&7)Thp dp',elopn,ent of a com pie."Jpragla- cial moraine at the margin of Sorbreen.NY Ffle51and. Vest,pltsbergen lournal of Glaciology.vol.&.p 717-73~. Boulton.G.S.(1%8)Flow t,lIs and rplated deposits on somp Vpstspltsbergpn glaCiers Journa'01 Glaciology.vol.7. p 391-412 Boulton.C.S.(1970)On the origin and transport of &Iacial dt"- t>ris in Svalbard glaciers.Journal of GlaCIOlogy.vol.9. p.131-24S Capps.SR (1940)Geology of the Ala,ka ra.lroad reg.on.U.S. Gpologlcal Survey BulietlO 907 Cooper.S.P Bock.I.Horowlll and D.Foran (197\)The use of ERTS .magpry In ,,'servo",management and opera- lion.New England D,vlSlon.Corp;of Engineers. Cseltey.B..Ir (1974)Reconna"sance geologiC ,nvestlgat,on In Ihe Talkeetna Mounta.ns.A'aska.U S.Geological Survey Open·File Report 74-147. Cse,tey.B.•Ir ..W.H Nelson.D.l lanes.N I.Sllneriong.R.M. Dean.M S Motrls.M.A.lanpherI'.I.G.Smith and M.l Silberman (1978)ReconnaISsance geologic map and geochronology.Talk""tna Mount..ns Quadrangle. northern part of Anchorage quadrangle.and soulh· wPst cornpr of Hpaly quadrangle.Alaska U.S. Geological Survey Open-F.le Report 76-SS8 A. Dean.KG.[1(79)A geologic evaluation of landsat satellite Imagery In mtenor Alaska).M.S.theSIS,UnlverSltv 01 Alaska.Fairbanks.Alaska (unpubllsh~). Eppl"y.R.II.11%5)EarthQu~ke hIStory of Ii'll'United Stat"s. ParI 1:Slronger earthquakes 01 the Un.ted Stales Rt"- vised ~llion (through 1%3).US.Department of Com- merce.Environmental Science ServIce AdministratIOn. Coast and Geodet,c Survey.Washington_O.C ..Reporl 41-1. Fhnt,R.E.(1971)Glacial and Quaternary Geology.N....York: John W,'ey and Sons. Forbes.R.B.,T E Smith.and T.l.Turner (1974)Comparalive ~trology and structure of the Maclaren.Ruby Range and Coasl Range Bells.implicaltons for offsPI along Ihe Denali Fault Syslem (abs.)Geological Sociely of America.Cordilleran Seclton.p 177 '-------_....--..._---...."':.0.,•.__~:- Gary.M .•R.McAfee.Jr ..and Cl,Wolf IEds.)(1972)Glos ...ry 01 Geologi.American Geololl,cal Institut~. Wa,hlnglon.0 C. Gatto.loW.l\97b}Ba~hne data on the oceanography of Cook Inlet,Alaska.CRREl Report 71>-2S ,o.00293S8. G"dney.l.and l.Shapiro (1975)Structural lineament,. ~'5mIClty and geology of ihe Talkeetna MountdlO!. Arpa.Alaska.U.S Army Corp,of Engineers.Alaska DlSt"cL Ancnorage.Alaska Gilluly_J.A.(Waters.and AO Woodfurd (1%8)PrlOc/pl", of GeoIOllY.San FrancISCo:W.H.Freeman and Com- pany. Graybeal.G E . F G.Hall.B.H Moore.and E.H.Schlosser (1974)ERTS-1 data in support of th"National Program 01 Inspection cI Dams.NASA SP-351.p 102J-1039 Haugen.RK.R.l.TUIn,lra.and CW.SlaughtPr (1979)A landsat data col/ecllon plat/orm at DeVil Canyon SIte. Upper Susitna Ba"n.Alaska.CRREL SpeCIal Report 79-2 AD I\ObIl SOB Isacks.B.,.Ol,ver and l R.Sykes (1968)SeISmology and the new global tectonics.lournal 01 GE.'Ophy,icat Research. vol.73.p.5aSS-5699 Kachadoo"an.R.(1974)Geology of the Devil Canyon darn site.Alaska.U.S.GpologlCal Survey Open-f'le Report 74-40 Kachadoo"an.R..D.M.HopkIns and D.R N.chols (19541 A preliminary ,,'porI of geolog,c factors aifeC!,ng high- way construction on the area between the SUSItna and Maclarpn R,vprs.Alaska.U.S.C"ologlcal SurvPy Open F,Ie Report. Kachadoo"an.R and T1 Pew~(19S5)Englnee"ng geology of the '0'them half of the Mt Hayes A-S Quadrangle. Alaska U S Geological Surve~Open Flip Report lahr.J C.and R.Kachadoorian (Undated)Preliminary geo- Joglc and seIsmiC evaluation .;,f the propo!tE"d DeVIl Canyon and \Yatana re~e!'"vOlr dreas.Susltna RIver. Ala,ka PrplimlOary U S Geolo~,cal Su'vpy Report la",,,,n.DE (1979)Sedlmenlo'o~'cal analysis of Ihe WPslern termmus r"g.on 01 Ih"Malanuska GlaCier.Alaska. CRREl Report n-9.AD A072ooo. McKen!'e_D P dnd R l Parker{19&7)Th~North Pacd,c:An e,amp/e of tectoOlcs on a sphere Nature.vol.21&.p. 127&-1280 McKIm.Hl.T l.Marlar and D.M.AndelSon (1972)The use of ER TS-1 'magery on the Nahona'Program for the In- ,pect'on of Dams CRREl Sp"cial Report 181.AD 7S4S79 McKim.H l and C ,.Merry (197S)Use of rpmote sensing to quant,fy construction matellal and to defon"g"olog,c I,neat'ons.Dickey-lincoln School lake.Prolect. Ma,ne CRREl SpeCial Report 242 AD A02327& McK.m.H L.l W Gatto.C.I M€rr~.D.H.Ander"'n and T l. Marlar (1975)land use/vegetation mapping on reSer- va"management.Me"'mack River BaSin CRRE l S.,.... c,al Reporl 233 AD 013490. McKim.Hl,l W.Gatto.c.J Merry_BE.Brockett.M A Bilello.I E.Hobble.and I Brown 1197balEnvironmen· tal analy,,,s In the Kootena'River rPll,on.Montana. CllllEl Spec,al Report 7&-13 AD A033500 McKim.H l,l W.Gatlo.C./.Merry.and ilK Haugen(197&bl Sk"lab Ima~ery'ApplicatIon to reser'f'O'(management In New England.CRRH Special Reporl 71>-7 AD 030329 36 _.n e .•,ai.F?>.;:..:::>z;KLo;--------------.«el .j.:;.;;-....t'e -j -,.'1 •h',r.to -..'...'t.,Q •1'1"'.,... ."".--_._-_._.__.-.~'--__'_..~~-----, ,.._-~"'".""'"......""'-.,.",.---...,~.__.""-+-"~,...-.....",,,,,.?_.,_.~,--., fr f I 1- ! l l f•f I f f t f ~ I. I. I. j / MofflL F H (1912)Headwall!r Region~of Gulkana and Su"t· na R;y.,,~.AI ..ka.U.S Geolog,cal Survey Bulletin 498. Natiooal Aeronautics and Space "'dmlnlStratlon (1'1721 N"SA Earth Resourc6 'Technology Satellite:ERTS-1 Data U~'Handbook.Coddard Space FlIght Center,Docu· ment No 71SD4249. O'Leary,0 W,,D.Friedman,and H.....Pohn (1'176)L,nea, menL lmear.lineation.Sam<.'propo,ed new 'landard, for old term~Ceologial Soclely of AmeriGl 8u/le/in. vol.87.p 146l-1469. PIa Ike<,G.[1%9)Tecton,cs of the March 27,1%4 ...Ia,ka Earthquake.U.S.Geo/og,cal Survey Pro/eH,onal Pape<54l-1 Richter,0 Hand N.""Matson.Ir (1971)Qualernary I...h,ng ,n the eastern Alaska Range Geolog/cal SOC/Ny of A"",,/ca Bul/elin,.vol.82.p 1529-1540. Richter,0 Hand D.L.lon6 (1973)The ,tructure and ,"a/,- graphy of ea.lern ""a.ka Range.Ala,ka,AmerIcan AI' ~oClatlon Pelroleum GeologlSu Memoli 19.p 408-420 Also "'Second Inlerna/iofldl Arclic Symposium Pro- c~jngl.American AHoCla/ion of Pelfoleum Geologlsrs Bullerm Rieger,S,O.B Schoephorsler and C E.FurbuI"(1979)Ex- ploratory >OIl survey of Alaska US Oeparlmpnt of "'gncuiture,Sod Con~rvalion Service Ruhe,R.V (1975)Geomorphology.geomolphic prOC6le,and ~urfrcjal gery/ogy.Boston.Mass.'Houghton MilUm Co. Sellmann.PV.,J Brown,RI.lewellen,H.McK,m and C Merry (197Sj The das"r,c.l!Ion and geomorphic Imph· cattOns of thaw lake-s on the ArchC Coastal PI.un. Alaslca.CRREl Research Report 344 AD 021200. Smith.T E and D,l.Turner (1974)Maclaren metamorphIC !>(oil of central ...Ia,ka (ab'tract).GeologICal SocIf'tV of America.Co,d1I1tt~an SectIon,p.257 Thornbury,W D.(1954)Principle,0/geomo<phology.N..... York:lohn Wilev and Son,.Inc. Tobin,D G.and l R Syke,(I%8}SeISmiCIty a~d lectonl"of the Northea'!ot PaCIfic Ocean.JournaJ of CMphVS.'Cdl Re,earch.vol.73,p 3821·3845 Turner,D L.T E SmIth.and R.B Forb"s (19;'4/CeoclvOtlol- ogy of ofhet alon~the Denali Fault SY'tem In ...Ia,ka (ab~trdctl Geologlca1 Society of A,tH.""Cc1.Cordillf"f"an Secllon,p.2b8. U.S."'rmy Corp,of Eng;neers,Alaska DIStl1ct [1978.0)Plan of sludy for Su,ilna hydropower fea"blllt,analy,,, Slalp of A1a,ka.lunp U.S.Army Corp,of Engoneers."'la,ka DIStrict 11978b)S.."tna h'tdropower feas,bllity analvsl!i.Ofdft [moronme-ntal A>l6,ment,"'nchorage.Ala,~a,Oecpm!>(or VanWormer,I D.I.Davle~,and l.Cpdnl'V (1974)SeISmICIty and pia Ie lectomcs on ,outh-central ...Ia,ka 8ulletln 01 Ihe SeIsmological Soc;p/y 0/Amer;u.vol 6-4.p 1467·1475 Walfe"L.R (1977)The Denair "'SVT remote ~"nll project. apphcahon on Ala,ka.In Proceedings 0/it SrmpmlUm on Norrh Amellcan fore,'Lands al LA/I/udes Nonh 0/ 60 d(>flrees.Unlversily of Ala,ka,F."rbank~,...Ia,ka, 19-22 September.P a5-107 Wobber.F.V and KR.Marlin (1973)hplotlahon of ERT5-1 imagery utiliZing snow enhanct"me-nt tectlluques lab,lract)Sympo,'um of S'llnlflcanl R6Uh~ERTS-1. 5-9 March. 37 ,.---'---'~----'--1...---'---".,.--., .i-_-..Ao·~W;{.r~~~~~~.~~----*-'.------- .~.__,..._.~,•..".~·~~"''"_'_'''C~'''''''~__'__._'''_"''''''''''''~.......-;oo.•....~-_.,__•__...._~_.-,__,.'...,_ r:." GLOSSARY· f· f Term Alluvial Back Slope Benioff Seismic Zone Colluvium Dendritic Drainage Pattern Earthquake Magnitude Eolian Epicenter Fault Fault Zone Fluvial Foot Slo\>e Definition Pertaining to or composed of alluvium,or deposited by a stream or running water. The slope at thE'back of a scarp;ego the gentler slope of a cuesta 01'of a fault block. A plane beneath the trenches of the circumPacific belt,dipping towards the continents at an angle of about 45°,along which earthquake foci cluster.It is sometimes referred to as the Benioff fault plane.Ac- cording to the theory of plate tectonics and sea-floor spreading.plates of the lithosphere sink into the upper mantle through this lone. A general term applied to any loose,heterogeneous, and incoherent mass of soil material or rock fragments deposited chiefly by mass-wasting,usually at the ba~ of a steep slope or cliff.e,g.talus,cliff debris,and ava- lanche material. A drainage patter:1 in which the streams branch irregu- larly in all directions and at almost any angle,resemb- ling in plan the branching habit of certain trees,and produced where a consequent stream ,::!ceives several tributaries which in turn are fed by small tributaries. A measure of the ground motiotl at a fixed distance from the epicenter and is stated in terms of the Gutenberg- Richter scale.,"Iagnitude is I)elieved to be related to the energy released by the earthquake and is determined from one or ".,ore instrument records,The magnitude scale is exponen,:ial in character so that an Increase of one lOmt in molgnitude s'gnof ies a len·told increase in ground mallon,or roughly a 6J-fold oncrease on energy release.The zero of the scale represents the smallest recorded earthquakes.The largest known earthquake magnitudes are about 8.75 (Eppley 1965). Pertaining to the wind. That point on the Earth's surface which is directly above the focus of an earthquake. A surface or lone of rock fracture along which there has been displacement,from a few centimeters to a few kilometers in scale. A fault that is expressed as a lone of numerous small fractures or of breccia or fault gouge,A fault lone may be as wide as hundreds of meters. Of or pertaining to a river or rivers. A general term for a hillside surface whose top part is the wash slope and that includes all the slopes of dim· inishing gradIent.. ~:-' " 'From Gary er al (1972)unless otherwise IndICated, 39 ~....,_.~•.__.~,."-....-----.....,...-•.~.•-"'_....,'",.-.......~,-,..."...'-.•".,'...-._-~,....._~-----'-....+-~.,...-..~--•.",.,.~._.,--.,--.•--".--~~."._.,. i .... Glaciofluvial Graben Hypocenter Lacustrine Lineament Modified Mercalli Scale Moraine Outwash Richter Scale Right Lateral Faull Scissor Fault Pertaining to the meltwatl'r streams f10winll from waslinl(IIlacier ICe and espt'c llv 10 the deposi"<,nd landforms produced by such str m~.as I.ame terr..ces and outwash pIa lOS. An elongate,relalively depressed crustal unit or block that is bounded by faults on its long sides.It IS a struc- tural fOt'm that mayor may not be geomorphologlcally expressed as a rift valley. The focus of an earthquake. Pertaining to,produced by,or formed in a lake or lakes. A mappable.simple or composite linear feature of a surface,whose parts are ""gned in a rectilinear or slightly curvilinear relationship and which differs dis- hnctly from the patterns of ad,acl'nt features and pre- sumably reflects a subsurface phenomenon.Their meaning has ~n much debated;some certainly ex· press valid structural features.such as faults.aligned volcanOt's.and zones of intense Jointmg with little dis- placement.but the meaning ot others 's obscure,and their ongins may be diverse.or purely accidental.Also, the term is widely applied to lines representing beds, lithologic horizons,mineral bandings.veins,faults. jomts,unconformities,and rock boundartes (O'leary et al.1976) One of the t'arthquake intemlty scales.having 12 divi- sions ranging from I (not felt by people)to XII (damage nearly total).It 's a reVISion of the Mercalli scale made by Wood and Nl'umann In 1931 Abbrt'v.MM scale. A mound,ridge.or oth",distmct accumulation of un- sorted,unstratified glacial dnft.predominantly till.de- posited chIefly by direct action of Illacll'r ic(>in a variety of topogr.Jpnic landforms that all'mdependent of control by the surfacl'on which the drift lIes Stratified detritus (chiefly sand and IIravel)removed or "washed out"from a glacier b\·meltwater streams and deposited in front of or beyond Ihe terminal mora me or the mariN>of an act've gldcier. The range of numerical values of eart:lquake mallnllude, devised in 1935 by the ,eismologist CF.Richter.Very smdll earthquakes.or mIcroearthquakes,can have nega- t,ve magnitude values In theory there 's no upper limit to the magOitude of an earthquake However,the strength of Earth materials produces an .lctual upper limit of slightly less than 9. A fault,the displacement of which IS "lIht-lateral separa· tlon.Movemem of a lateral fault along which.in plain view,the SIde Opposite the ob,erver appears to have moved ,0 the fight. A fault on which there is incrl'as'"8 offset or separation along the <trike from an ini"al point of no offset,With re- verse oflst't 10 the Opposite dorection The separation is 40 1 ,.__."_,••-~_~~,~_.,_"~,,._•••,.,.~>__,,.~"~•"-",_,__,,-__._,,,-__._,...,_,..__.~..................__,..__',.,-,"1- Ir I ~ Strike-Slip Fault Subduction Zone Su~rposed Talus Thrust Fault Till , ~ j ! ( t.....tQU1U &u &<# commonly attributed to a SClssor""-e or pivotal move- ment on the faufl.whert>as it IS actuallv the result ot uni- form strike-slip movement along a fault across a synclinal or ant,cllnal fold A fault.the actual movement of which is parallel 10 the strike of the fault An elonllate rellion along whIch a crustal block descends relative to another crustal block.e II·the descent of the Pacilic plate beneath the Andean plale along the Andean trench. Shortent"d form of superimposed Superimposed means a stream or drainage svstem let down from above bv ero- SIon through the formations on which It was developed onto rocks of dIfferent structure lYing unconformably beneath Rock fragments 01 any size or shape (usually coarse and angularl de;ived from and Iyin!:at the base of a cliff or very steep.rocky slope A fault with a dip of 45°or less in which the hanging wall appears to have mov('d upward relative to the footwall. Horilontal compres~lon rather than vertlca'd"place- ment is its characteristIc ieature. Cenerally unconsolidated and unstratofied sediments.de- posited directly by a Illacn'r ,,·,thout subsequent re....ork· Inll and r('sedimentatlon bv olher proces;es of the glaCIal ('nvllonment It oft('n ConslsH of d IWINog('n('ous mixture of c1JY.5dnd.grdvel.and bould('rs vdrying wielely In SIze ,lnd shdpe (based on lolwson 1979) 41 ...•k ,•.,.•~--_.-.- ,. .~.: A facsimile catalog card tn Library of Congless MARC format is reproduced belo~. Gatto,L.W. Environmental analysis of the Upper Susitna River Basin using Landsat imagery /hy L.W.Gatto,C.J.Merry,H.L.McKim, and D.E.Lawson.Hanover,N.H.:U.S.Cold Regions Research and Engineering Laboratory;Springfield,VA.:available from National Technical Information Service,1980. viii.56 p ••illus.;27 em.(CRREL Report 80-4.) Prepared for Directorate of Civil Works -Office,Chief of Engineers by Corps of Engineers,U.S.Army Cold Reeions Research and Engineering Laboratory. Bibliography:p.36. 1.Aerial photography.2.Environmental surveys.3.Mapping. 4.Satellites (artificial).I.C.J.Merry,co-author.II.B.L. McKim,co-author.III.D.E.Lawson,co-author.IV.United States.Army Corps of Engineers.V.Army Cold Regions Research and Engineering Laboratory,Hanover,N.H.VI.Series:CRREL Report 80-4. L :.----:--:-:--,,-_._--_.-----.'_.~-...~------------,_.__._-_.------- I