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Magnetotelluric Survey Hot Springs Valley, Akutan AK 2009
WesternGeco MAGNETOTELLURIC (MT) SURVEY Hot Springs Valley, Akutan, Alaska Operational Report Volume 1 of 1 Prepared for City of Akutan, Alaska By GEOSYSTEM WesternGeco EM Milan, Italy Effective date: October 2009 Revision History ag Effective Date Description Prepared by Reviewed by Approved by 01 17 September 2009 Alessandra Battaglini 02 12 October 2009 Mark Kitchen 03 14 October 2009 Stephen Hallinan | Stephen Hallinan City of Akutan Akutan MT 2009 survey Operational Report CONTENTS SUMMARY 1 SURVEY AREA, LOGISTICS AND HSE.. 1.1 WORK AREA 1.2 COORDINATE SYSTEM... 1.3 OPERATIONS 1.4 HSE SUMMARY 2 MT DATA ACQUISITION 2.1 PARALLEL SENSOR TEST 2.2 SITE PREPARATION AND LAY-OUT. 2.3 RECORDING PARAMETERS 2.4 QUALITY CONTROL 3 MT DATA PROCESSING... 3.1 ROBUST PROCESSING 3.2 DATA PRESENTATION... 3.3 SIGNAL AND NOISE 4 BIBLIOGRAPHY Appendix A GLOSSARY .... Appendix B PERSONNEL AND SURVEY HISTORY B.1 MT PERSONNEL B.2 MT SURVEY HISTORY... Appendix C MT STATION COORDINATES C.1 MT Sounding COORDINATES Appendix D EQUIPMENT AND DATA FORMATS...........cssssssssssstessssseessssseessssnesssneesssneessneneessnneesss D.1 TECHNICAL SPECIFICATIONS... D.2 MT DATA D.3 Time Series D.4 EDI Files Appendix E MT PARAMETERS sivsccsssccsccossssosseonsssccssesosteraveescovssraverscssstveesosteenossevossehasstosssduaeseabansuvacvaezs Appendix F MT DATA PLOTG................ Appendix G DIGITAL DATA ON CD FIGURES: Figure 1. MT station locations on topographic base map (Transverse Mercator, WGS84).... Figure 2. Five-channel MT layout sketch showing main components. (No Hz WAS FECOFEM iN Present PFOjECt).......secscseeeseessseesessneseessneesssneeeessncsssnneesssneessnneeensnesesnneessne 5 GEOSYSTEM - WesternGeco EM i October 2009 City of Akutan Akutan MT 2009 survey Operational Report Figure 3. Geomagnetic activity (Ap index) for the survey period. Dates are referred to UTC time Figure 4. Average wind speed during survey (mph).. Figure 5. Time Series at 1.17Hz for sites A002 (Ex, Ey, Hx, Hy), A032 (Hx, Hy) and A048 (Hx, Hy) showing poor correlation between channels due to high Winds ON SeptEMbeEr 8 .sessevssosevseessssssssssssessnssasnsssssssssssssssesesssessssesssssessssusuuussnssssnnsnsnss 11 Figure 6. Time Series at 1.17Hz for sites A002 (Ex, Ey, Hx, Hy), A032 (Hx, Hy) and A048 (Hx, Hy) showing good correlation between channels without high Winds on September 11° ..ecsccsscsssssssssssesssssssssessssssssssssssssssssssessssssssecssssssssssesssssssssssssssssuseeesssse 11 Figure 7. Calibration curves for Metronix coils MFSO7-005........scsscssssssssssssessssesssnesssseesnesesns D-4 Figure 8. MTU-5A #1563 calibration curve Figure 9. A graphical representation of the time series file format. The scans within one record span either one second (Bands 3, 4, and 5) or 0.1 second (Band 2). Records always begin on a UTC second, but not necessarily On CONSECUTIVE UTC SECOMAS. .....sesssseesssesssesressiseseesnniessneennneesneesneessees DB Figure 10. Coordinate axes and component identifications for 5-component MT SSL czxesetecsvasteseetsetusenssteurcotscesssvsetosvonectauesbsSlsssvursdtvsevostoursedssteastesstraceveerseeedstei . E-11 TABLES: Table 1. Safety statistics during the survey period... Table 2. MT recording frequency schedule (local time) for Phoenix equipment. . Table 3. Summary of tag byte assignments............. Table 4. Tag byte 14 status codes..... Table 5. Tag Byte 20, Sample rate units GEOSYSTEM - WesternGeco EM ii October 2009 City of Akutan Akutan MT 2009 survey Operational Report SUMMARY Under contract from City of Akutan, WesternGeco’s Land EM group carried out a total of 51 magnetotelluric (MT) soundings in Akutan area, Alaska. The Acquisition, Operations and Data Processing are reported here; 3D resistivity inversion modelling is the subject of a separate report. The MT survey was carried out between August 29th and September 12th, 2009, in a total of 10 production days, and 2 stand-by days. During 1774 total man hours worked, no LTI incidents were reported. Four-component (no Hz) broadband MT data were acquired by two independent field crews, deploying 24-bit, GPS-synchronized, Phoenix MTU-5A MT receivers, yielding an average of five MT soundings per 24 hours. Two sites within the field area were chosen to host stable horizontal magnetometers for the duration of the survey. One of these was used as the remote reference location and the second was used as the magnetic field measurement for the telluric only sites. The five roving systems were a combination of telluric+magnetic and telluric only sites in order to measure sites in the difficult terrain. Time series were processed using robust, remote referencing techniques. The measured and processed data quality was generally good. Few sites have lower s/n ratio due to vibrational noise on the magnetometers induced by the high winds, prelevant during the survey period, and low signal amplitudes observed on several days. Finally, good quality MT data covering the 7-decade range 0.001 to 10,000Hz was processed at all sites, notwithstanding gaps over the low signal, dead bands around 2000 Hz and less commonly at 0.1 Hz. GEOSYSTEM - WesternGeco EM 1 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 1 SURVEY AREA, LOGISTICS AND HSE 1.1 WORK AREA An MT survey of 51 stations was carried out over Akutan island in Alaska, where the station spacing was between 0.4 and 0.5 km (Figure 1, see also Plate 1 for a larger scale). The present report discusses MT acquisition and data processing, QHSE and operations; the 3D resistivity inversion modelling is the subject of a separate report. 16S 16600 16835 1890 64E 1650" Bevation meters 1280 1150 1050 950 ‘6008000 850 750 650 550 tee 450 350 250 150 ‘6000000 pad Bathymetry ‘son8000 meters ° +100 wor -200 -300 400 -800 ‘8390000 600 -700 800 Figure 1. MT station locations on topographic base map (Transverse Mercator, WGS84). 1.2 COORDINATE SYSTEM All map coordinates are reported in the following system: Metric Coordinates: Projection: Transverse Mercator True Origin 165°00' W, 0°00' N Coordinates at Origin 500,000m E, 0.000m N Datum: WGS84 Spheroid: WGS84 Geographic Coordinates: Datum: WGS84 Spheroid: WGS84 Elevation Orthometric: Extracted from 90m (SRTM) DEM, in meters relative to mean sea level GEOSYSTEM - WesternGeco EM 2 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 1.3 OPERATIONS Scouting, access permitting and local logistics facilitation were coordinated by the City of Akutan, while Geosystem provided equipment, technical personnel and logistics. Advance crews mobilized to Akutan on August 23rd, where a temporary office was set up at the Bayview Hotel in Akutan, for project management, data processing, and instrument maintenance. Following arrival of field camp, shipped in from Anchorage, and technical personnel, MT equipment was tested during August 28". Data acquisition began on August 29th, and was completed on September 12th, having measured a total of 51 MT stations. Site access from the field camp was entirely by walking. MT field crews were stationed at a tented camp located in the Akutan valley near the saddle into Hot Springs Valley, which served as the field base and battery charging location. Daily supplies and field data were moved between the field crews and the operations base in Akutan by skiff chartered in Akutan; a 21 foot Packman Hull vessel. Two field crews were deployed, producing up to 5 MT sites per day. Given the predicted soft conditions and high winds, two sites within the field area were chosen to host stable magnetometers for the duration of the survey, and no vertical magnetic component (Tipper, Hz) was deployed. Five MT stations recorded on a very high wind days were repeated to improve signal to noise ratio during the survey. Contact between the field crews was maintained through the Iridum satellite network and local cellular service where available. UHF radios were used for communication between the field crews and for communications to the operations base where possible. Personnel, production and equipment are listed in Appendix B, Appendix C and Appendix D. GEOSYSTEM - WesternGeco EM 3 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 1.4 HSE SUMMARY The Schlumberger-WesternGeco & Geosystem QHSE System was applied with respect to local conditions. All project personnel were inducted on the basic safety and local particularities: e Basic Training: QHSE, Risk analysis and minimization, First Aid, SIPP training (Schlumberger Injury Prevention Program); e Small boat training. At the startup meeting, Geosystem’s operational safety and environment program was implemented; later updated during the survey according to varying conditions. Table 1 summarizes the safety record reported over the entire survey period. Table 1. Safety statistics during the survey period. Life Loss Life Loss - Total 0 Automotive Total AA's - Automotive Accidents (CMS) All the access and survey trips, in boat or on foot, were carried out in accordance with the Project Journey Management Plan, addressing location specific risks; the field crews had daily pre-determined journey plans and Journey Evaluation forms completed before each trip. The Project Party Chief was designated as Journey Manager in charge of ensuring that established practices were followed, and the crew location monitored continously. GEOSYSTEM - WesternGeco EM 4 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 2 MT DATA ACQUISITION Broadband Tensor MT (no Hz) with remote Technique: reference. Data acquisition: Full Time series recorded. Frequency range: 0.001 — 10,000Hz. Recording system: 5-channel GPS synchronized Phoenix MTU-5A. Magnetic sensors (details in Appendix D): H., H, (MFS-07) Metronix magnetic sensors. 2(E,, E,) symmetric 100m lengths, with 4x50m Electric sensors (details in Appendix D): dipole wires and 5xnon-polarisable Pb-PbCI2 electrodes. MT station layout (see Figure 2): Varying setup azimuth. Convention after rotation: E, - North (N 0°); E, - East (N 90° E); H, - North (N 0°); H, - East (N 90° E). Data processing (see chapter D.3): Robust remote reference technique. Acquisition & electrode processing unit Ex electrode Common electrode electrode electrode Magnetic sensors Figure 2. Five-channel MT layout sketch showing main components. (No Hz was recored in present project) 2.1 PARALLEL SENSOR TEST Prior to the survey start-up, all coils were checked in a parallel sensor tests conducted by the operators prior to site deployment on the first day. The magnetic sensors were buried to depths of about 10cm, aligned North-South, and each was located parallel to and about 2m from its neighbour. Given identical sensor and acquisition systems, one would expect to see very similar outputs both in time and frequency domain: resulting coherencies should be greater than 0.9 between pairs of like sensors, and amplitude and phase transfer functions close to the theoretical values of 1.0 and 0.0° GEOSYSTEM - WesternGeco EM 5 October 2009 City of Akutan Akutan MT 2009 survey Operational Report respectively. In this way both the magnetic coils and the individual MT receiver channel boards could be verified. Electric dipole wires were checked for correct length (50m) and obvious external damage to the protective insulation. Coil cables were similarly tested for correct pin-to-pin continuity and the absence of cross-channel interference (partial grounding between pins). 2.2 SITE PREPARATION AND LAY-OUT Crews located the new sites using a hand-held GPS unit pre-programmed with the proposed sounding locations, in conjunction with maps showing the sounding locations. Each MT crew moved to the new sites upon completion of data downloading and retrieval of equipment from the previous recording site. Arriving at a new site, the first course of action was to select the site centre so as to minimize topographic relief between electrodes, avoid possible interference sources, extend the dipoles (4x50m wires) and install the electrodes to allow sufficient time for stabilization. In order to reduce the footprint, and to increase productivity over this terrain (100% walking to all sites), the magnetic field (Hx, Hy) has been recorded at two permanently installed MT sites and at least one roving location, allowing the crew to move four other relatively light E-field only (Ex, Ey) MT sites per day. This hybrid approach is a valid way of reducing hardware required, increasing deployment speed for each MT site, and reducing footprint (less magnetic coil holes to dig in). The selected coil sites were located to avoid overly swampy areas, with motion noise common to the soft boggy terrain. A third and sometimes fourth set of coils were installed at sites as time and access permitted. Trenches 30-50 cm deep were dug to bury the horizontal coils to minimize wind vibration and to provide thermal stability at the all magnetic site locations. The magnetic sensors were buried at a distance of 5 m from the acquisition unit. Horizontal magnetic fields were recorded at 3 or 4 of the MT sounding locations, including the 2 stable magnetometer sites, each day. The operator measured SP (Self Potential) and contact resistance across the dipoles and recorded them in the field books, together with the magnetic sensor serial numbers and the dipole lengths applied. In case of high contact resistance, the electrodes were re-buried and re-watered in order to reduce the resistance. GEOSYSTEM - WesternGeco EM 6 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 2.3 RECORDING PARAMETERS The recording schedules shown in Table 2 were designed to maximize data acquisition in the mid to long periods and to provide a high frequency window with the magnetometers in high frequency mode near the beginning of the run. Time series files are stored in hour long blocks to keep the data recorded with the magnetometer chopper on and chopper off modes in separate files. The chopper off mode is for high frequency data acquisition, while chopper on mode is for low frequency acquistion. Table 2. MT recording frequency schedule for Phoenix MTU-5a equipment. Band Sampling Frequency Recording interval (Time in UTC) Local time = UTC-8 hours TS2 | 24000 Hz / Magnetometer chopper off | 4 records of 2400 points every 15 seconds, beginning at (high frequency) 04:00:00 and ending at 06:00:00 TS3 2400 Hz / Magnetometer chopper off | 2 records of 2400 points every 15 seconds, beginning at (high frequency) 04:00:00 and ending at 06:00:00 TS3 2400 Hz / Magnetometer chopper on | 2 records of 2400 points every 15 seconds, beginning at (low frequency) 18:00:00 and ending at 04:00:00, then beginning at 04:00:00 and ending at 16:00 TS4 150 Hz Hz / Magnetometer chopper off | continuous from 04:00:00 and ending at 06:00:00 (high frequency) TS4 150 Hz Hz / Magnetometer chopper on | continuous beginning at 18:00:00 and ending at 04:00:00, then (low frequency) beginning at 04:00:00 and ending at 16:00 GEOSYSTEM - WesternGeco EM 7 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 2.4 QUALITY CONTROL Quality control procedures were taken at each stage of data acquisition. The MT crews assessed the status of the equipment on a daily basis, as described above. Field records were kept, to track possible equipment problems, with the following information: Coordinates; Telluric lines lengths and azimuths (geographic North); Contact resistance and self-potential; Magnetic sensor and MT receiver serial numbers. e Weather and terrain conditions The field layout parameters and sketch are included on the Time Series HD. Further quality control measures were completed in the field office. Time series data from the same recordings were brought together on the processing computer and inter-channel correlation was checked. Any discrepancies noted were relayed to the operators, so that suspect equipment could be set aside until further testing was undertaken. GEOSYSTEM - WesternGeco EM 8 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 3 MT DATA PROCESSING Data were processed at the field office within 48 hours of recording, using robust, remote techniques. All time series data is recorded and stored. For data processing the following procedures were used: Visual inspection of time series segments using WinGLink, developed by Geosystem; Cascade decimation with robust sorting for AMT frequency band processing; Robust processing of time series using Larsen code, by individual bands; Merging of individual bands to form a complete sounding curve. Fa S2 BS|= 3.1 ROBUST PROCESSING The robust, remote reference MT processing code described by Larsen et al. (1996), and subsequently implemented and upgraded by Geosystem, was used to estimate a smooth magnetotelluric transfer function (i.e. impedance) relating the electric and magnetic field data. The original and decimated time series bands provided input data. The code first determines the transfer function between the remote and local magnetic fields, with the assumption that the remote magnetic field is noise free. This iterative process corrects the local magnetic field for outliers in both the frequency and time domains. The magnetic fields are then used in an iterative re-weighted method to determine the impedance tensor. During the iterations, the electric fields are corrected in both the frequency and time domains, utilizing a smooth MT transfer function to estimate the electric field data from the magnetic fields. This procedure is repeated for each time series band and the complete sounding file, spanning a 7-decade frequency range from 0.001 to 10,000 Hz, is obtained by merging the results. The final MT parameters are written to standard EDI files, one per sounding. 3.2 DATA PRESENTATION The calculated MT parameters are presented as digital files on CD in Appendix G: 1. as standard format EDI files (format described by Wight, 1988) 2. within a WinGLink database. In the WinGLink database, plots for each MT site include the following interpretation parameters, rotated to analytic direction obtained by robust processing: = apparent resistivities, p, and p,,; = phases, >, and o,; = impedance rotation and strike; tipper strike (geographic North); = impedance skew and ellipticity; = tipper magnitude; = smooth D+ curve for each mode. Data have been edited to mask noisier segments. A smooth curve, computed from the D+ function (Beamish and Travassos, 1992), is fitted to each component. Data which are geophysically plausible should lie close to this curve, except in the case of severe 3D behaviour. GEOSYSTEM - WesternGeco EM 9 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 3.3 SIGNAL AND NOISE MT signal strength was highly variable during the survey period as indicated by the Geomagnetic activity index (Figure 3). Besides natural magnetic activity, the data quality was also influenced by wind-induced vibrational noise. Coils were buried and E-lines weighted down, but ground was “pumped” by the strong wind gusts common in the Aleutians (Figure 4). To improve signal to noise ratio, one day's recording on a particularly windy day, September 8th, was later repeated. Note this high wind period unfortunately coincided with low signal also. Sites on the ridge lines at higher elevations were more affected by wind noise in general. Enen in the the low-lying swamp areas, high winds did have some effect on data quality. A few recordings had animal disturbance of the sensors, but with an adequate amount of data being recorded prior to the distubance. Increased application of a bitter liquid to the cables helped to reduce incidents of animal disturbance. — ee = ~ Akutan MT acquisition period Figure 4. Average wind speed during survey (mph) GEOSYSTEM - WesternGeco EM 10 October 2009 City of Akutan Akutan MT 2009 survey Operational Report An example of wind noise induced noise is displayed in Figures 5 and 6. The poor correlation between the channels at sites A002 and the 2 fixed magnetometer locations (A032 and A048) is visible in data recorded on September 8" when winds were about 40 mph (Figure 5). The sites were reoccupied on September 11", when wind speeds were about 10 mph. Good correlations between the channels are observed as shown in Figure 6. ‘<_< _——— ~ — 3 ee ee : aa ae A002 : Ey | $$ mea A002 me Hx é seal Ao 7 iy 2 Sith tae-iigei epee iohetytey sa 00: = Hx | é ramreod A032 =m iy 3 ssereal A032 a i | : cenit AO: Hy i a M" . A048 Figure 5. Time Series at 1.17Hz for sites A002 (Ex, Ey, Hx, Hy), A032 (Hx, Hy) and A048 (Hx, Hy) showing poor correlation between channels due to high winds on September 8”. 3 . —————— OOO ~~ A002 Ey * pe NN »pmAL we re g nee entenenritin | Way item tanicantnn cen aly Teoma aa eee parwsooy [eect nrtnnan tt imnernnirarineana yay WM a rence geen ene peace rene rir i vn Figure 6. Time Series at 1.17Hz for sites A002 (Ex, Ey, Hx, Hy), A032 (Hx, Hy) and A048 (Hx, Hy) showing good correlation between channels without high winds on September 11”. GEOSYSTEM - WesternGeco EM 11 October 2009 City of Akutan Akutan MT 2009 survey Operational Report 4 BIBLIOGRAPHY Beamish, D., and Travassos, J. 1992 The use of D+ in Magnetotelluric interpretation: J. Chave, A.D., and Thomson, D.J. Larsen, J., Mackie, R.L., Manzella, A., Fordelisi, A., and Rieven, S. Vozoff, K. Wight, D.E. http://www.swpc.noaa.gov/ftpmenullist s/geomag.html http://www.usgs.gov/ 2004 1996 1991 1988 2009 2009 Appl. Geophys 29, 1-19. Bounded influence magnetotelluric response function estimation, Geophysical Journal International 157 (3), 988-1006. Robust smooth magnetotelluric transfer functions: Geophysical Journal International, 124 801-819. The magnetotelluric method. In Electromagnetic Methods in Applied Geophysics, Vol2B 641-711, pub. SEG. SEG MT/EMAP Data Interchange Standard, Revision 1.0: SEG, Tulsa, OK, 91pp. Geomagnetic A Index, Estimated Planetary National Elevation Dataset (NED) GEOSYSTEM - WesternGeco EM 12 October 2009 City of Akutan 1D 2D 3D bgl bs! (asl) Coils Conductance Conductivity Contact resistance E-line EM E.andE, f H,,H,, and H, Induction arrow LaToracca skew angle mmsl Mode (TE or TM) Occam inversion Akutan MT 2009 survey APPENDIX A GLOSSARY The earth is assumed to be made up of homogeneous horizontal layers Geology is assumed to be uniform along strike, but varies in the dip direction. Geology varies in all 3 directions (x, y, and z) Below ground level Below sea level (above sea level) Sensors used to measure time-varying magnetic fields For a layer, product of layer thickness x conductivity (Siemens, S). See also Total Conductance, below. 1/resistivity (in S/m). Resistance of the electrode pot relative to a ground, measured in Q2. Cable used to measure the electric field Electromagnetic Electric field strengths, in units of mV/km, measured in the x and y directions respectively. frequency, in Hertz (Hz) Magnetic field strengths, in units of nT, measured in the x, y, and z directions (z positive upwards). Real part of the vector Ir. 7, |, illustrating the relation between the vertical and horizontal magnetic field components from H. =7.H, + T,H,, plotted to show direction towards an assumed 2D line-source (i.e. towards the conductor in the so-called reversed convention). =90°-(6,,), where 6,, is the angle between the major axes of the E and H polarization ellipses. Since this angle, should be 90°, the La Toracca skew angle should be zero under 1 or 2 D conditions. In 3D conditions, the E field may be distorted (i.e. rotated), resulting in non-zero values. meters above Mean Sea Level In a 2D world, the AMT/MT impedance is decomposed into two orthogonal components parallel (TE, or Transverse Electric) and perpendicular (TM, or Transverse Magnetic) to strike. In 1D and 3D situations the definition has limited value. Inverse modeling of geophysical data in which no a priori assumptions (e.g. the resistivity/thickness distribution) are made. Rather, the simplest model consistent with the data is found. Named for the 14th century philosopher William of Occam (see Occam, 1324, Quodlibeta, Book V: “Plurality is not to be assumed without necessity”). Period Inverse of frequency (1/f). Commonly used instead of frequency in describing the low frequency range in AMT/MT (defined in seconds, s) Pot Potential electrode: sensor at the end of the E line for measuring the electric field Pp apparent resistivity in Qm Prax aNd O,,,, The higher of the two apparent resistivity curves and its associated impedance phase. Py apparent resistivity calculated from E, and H, Py apparent resistivity calculated from E, and H, GEOSYSTEM - WesternGeco EM A-1 October 2009 Operational Report City of Akutan RMS error Roughness (of 3D resistivity model) Sensitivity Matrix, A'A Static shift Static stripping TD Tipper Tipper strike Top of conductor Total conductance Akutan MT 2009 survey Operational Report y (obs — pred)? npts var where obs and pred are the observed and predicted data responses (real and imaginary impedance tensors elements over the frequency range used and the stations employed in the inversion), npts is the number of data points, and var is the defined variance. This is defined as the integral over the 3D model of L'L- m, where L is the Laplacian and m is the model resistivity. Interfaces in the resistivity are indicated in the model volume by zero-crossings in Roughness. In that this parameter is a fourth derivative, it is inevitably prone to noise, but in compensation aids in identifying the most likely position of an interface. A(response) A(model) the modeled data due to a small change in the model parameter. This shows the sensitivity of the response to a particular 3D model, for each cell of this 3D mesh. Frequency-independent shift of AMT/MT apparent resistivities along the resistivity axis, caused by local electric field distortion. The sensitivity matrix 47 4= represents the amount of change in A method of correcting static shift. At a user-selected (normally high) frequency the impedance is forced to a uniform 1D solution at the actual rotation angle, such that xy and yx apparent resistivities have identical absolute values. The corresponding e-field correction is then applied for all frequencies, and impedance re-calculated at the same orientation angle. Stripping therefore attempts to correct static shift via the impedance distortion, rather than simply block-shifting the (derived) apparent resistivity curves. Total depth (of a well). Ratio of the vertical magnetic component H, to the horizontal magnetic field components H, and H,. Since the vertical component (noise excluded) is the output of a system (the earth) to which the two horizontal components are the input, its absolute value should not exceed 1 (see induction arrow). The geographic orientation in the horizontal plane of the vector relationship between the magnetic field components (tipper), taking real and imaginary parts into account. In a 2D earth, the tipper strike is perpendicular to the induction arrow direction, and shows the um 2D geo-electric strike. A surface interpreted from a resistivity distribution (e.g. 1D layered earth models or 3D resistivity volume in the MT case ) depicting the elevation of the top of the (principal) conductive horizon. Shown as contour map or line on cross-section. Units are m msl. The conductivity (=1/resistivity), integrated to a specified depth z: TC= > Az, / p, , where Az is the thickness of the ith layer and p, its resistivity. 0 GEOSYSTEM - WesternGeco EM A-2 October 2009 City of Akutan Akutan MT 2009 survey Operational Report APPENDIX B PERSONNEL AND SURVEY HISTORY B.1 MT PERSONNEL The crew list includes regular and rotation personnel IMT Patty Chet tetstctecssstscsassstctotctetstcca Mark Kitchen MT Crew Operators: .........ssseseeeeeee Jennifer Livermore ssrasscase asesuasstopisusenuessetsasesssescessesssistaraca soca Jesus Barrios tatabaleae dueutsastsbsntatasosarcoai@verasctantsastonisanataed Chris Jones Field Assistants (3 per crew) Alec Sandberg, Brett Willis, Matthew Bereskin, Dave Barck, Don Jon Tcheriponoff Captain Vessel: oo... sssesseesseesneesnees Dmitri Tcheripanoff Client representative: .........esesee Pete Stelling B.2 MT SURVEY HISTORY The site with gray shading is a re-measured MT sounding. Date Activity Crews Production 20-Aug Mark Kitchen to Anchorage All Crews 21-Aug Pack - 1st equip - DUT All Crews 22-Aug Chris Jones in Anchorage All Crews 23-Aug 1st equipment to Akutan All Crews 24-Aug 2nd equipment to Dutch All Crews 25-Aug 2nd equipment to Akutan All Crews 26-Aug Taiga camp set up All Crews 27-Aug Continue to set up camp All Crews 28-Aug Crews to camp, PST All Crews 29-Aug MT Production Crew_1 A033 A032 A031 A024 29-Aug MT Production Crew_2 A040 A041 A048 30-Aug MT Production Crew_1 A025 A030 A037 30-Aug MT Production Crew_2 A042 A046 31-Aug MT Production Crew_1 A034 A035 A036 31-Aug MT Production Crew_2 A047 A049 1-Sep MT Production Crew_1 A026 A027 A028 1-Sep MT Production Crew_2 A043 A050 2-Sep MT Production Crew_1 A021 A022 A029 2-Sep MT Production Crew_2 A045 A051 3-Sep MT Production Crew_1 A016 A020 A023 3-Sep MT Production Crew_2 A038 A044 4-Sep Rest day Crew_1 4-Sep Rest day Crew_2 5-Sep MT Production Crew_1 A012 A017 A018 GEOSYSTEM - WesternGeco EM B-1 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Date Activity Crews Production 5-Sep MT Production Crew_2 ed A051 6-Sep Weather standby Crew_1 7-Sep MT Production Crew_1 A009 A010 A011 7-Sep MT Production Crew_2 A045 A052 8-Sep Bad weather - no data Crew_1 A007 A008 A002 8-Sep Bad weather - no data Crew_2 A040 A039 9-Sep Weather standby Crew_1 10-Sep Sites on ridge - too windy Crew_1 10-Sep MT Production Crew_2 A014 A019 11-Sep MT Production Crew_1 A002 A007 A008 11-Sep MT Production Crew_2 A013 A015 12-Sep MT Production Crew_1 A001 A006 A053 12-Sep MT Production Crew_2 A003 A004 13-Sep Pick up last sites All Crews 14-Sep Demob camp All Crews 15-Sep Dismantle equipment - pack All Crews 16-Sep Load container Crew_1 16-Sep In Dutch Harbor Crew_2 17-Sep Waiting for flights All Crews 18-Sep In Dutch Harbor All Crews 19-Sep Waiting for flights All Crews 20-Sep Waiting for flights All Crews 21-Sep Made Anchorage All Crews 22-Sep Crews demob Anchorage GEOSYSTEM - WesternGeco EM B-2 October 2009 City of Akutan Akutan MT 2009 survey Operational Report APPENDIX C MT STATION COORDINATES Coordinate system as described in paragraph 1.2. C.1 MT SOUNDING COORDINATES Sounding | Easting (km) | Northing (km) | Longitude (°' ") Latitude (°'" Elevation (m msl) A001 443112 6002266 -165 5217 54 9 55 21 A002 443497 6001734 -165 51 55 54 9 38 129 A003 444126 6001708 -165 5121 54 9 38 46 A004 444581 6001875 -165 50 56 54 9 43 60 A006 442405 6002260 -165 52 56 54 9 55 25 A007 441531 6001243 -165 53 43 54 9 21 401 A008 442177 6001365 -165 53 8 54 9 26 313 A009 442673 6001435 -165 52 40 54 9 28 185 A010 443130 6001420 -165 5215 54 9 28 167 A011 443521 6001270 -165 5154 54 9 23 136 A012 443967 6001252 -165 5129 54 9 23 72 A013 444488 6001263 -165 51 0 54 9 23 6 A014 444916 6001300 -165 50 37 54 9 25 7 A015 445425 6001389 -165 50 9 54 9 28 1 A016 443562 6000609 -165 51 5 54 9 2 48 A017 444005 6000851 -165 51 27 54 9 10 19 A018 444480 6000771 -165 51 0 54 9 7 9 A019 445103 6000886 -165 50 26 54 9 ul 85 A020 441299 6000262 -165 53 55 54 8 50 317 A021 443185 6000186 -165 52 11 54 8 48 44 A022 443728 6000094 -165 5141 54 8 45 16 A023 444109 6000475 -165 51 21 54 8 58 12 A024 444510 6000192 -165 50 58 54 8 49 68 A025 444965 6000215 -165 50 33 54 8 50 194 A026 441162 5999466 -165 54 2 54 8 24 350 A027 441893 5999807 -165 53 22 54 8 35 75 A028 442483 5999666 -165 52 50 54 8 31 53 A029 443009 5999701 -165 52 21 54 8 32 28 A030 443613 5999591 -165 51 47 54 8 29 39 A031 444050 5999853 -165 51 23 54 8 37 70 A032 444515 5999730 -165 50 58 54 8 34 88 A033 445053 5999720 -165 50 28 54 8 34 75 A034 441587 5999317 -165 53 39 54 8 19 239 A035 442051 5999145, -165 53 13 54 8 14 134 GEOSYSTEM - WesternGeco EM C-3 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Sounding | Easting (km) | Northing (km) | Longitude (° ' ") Latitude (°'") Elevation (m msl) A036 442680 5999265 -165 52 39 54 8 18 35 A037 443184 5999305 -165 52 1 54 8 19 41 A038 444070 5999345 -165 51 22 54 8 21 277 A039 444644 5999357 -165 50 50 54 8 22 108 A040 445030 5999277 -165 50 29 54 8 19 20 A041 445502 5999251 -165 50 3 54 8 19 14 A042 446002 5999240 -165 49 36 54 8 18 94 A043 442633 5998529 -165 52 41 54 7 54 281 A044 443136 5998694 -165 52 ~—-:13 54 7 60 282 A045 443848 5998915 -165 51 34 54 8 7 327 A046 444633 5998618 -165 50 51 54 7 58 203 A047 445128 5998514 -165 50 23 54 7 55 204 A048 445606 5998656 -165 49 57 54 7 59 13 A049 446122 5998788 -165 49 29 54 8 4 18 A050 446015 5998325 -165 49 34 54 7 49 4 A051 442125 5998276 -165 53 8 54 7 46 399 A052 441345 5998476 -165 53 62 54 7 52 416 A053 441826 6002207 -165 53 28 54 9 53 61 GEOSYSTEM - WesternGeco EM C-4 October 2009 City of Akutan Akutan MT 2009 survey Operational Report APPENDIX D EQUIPMENT AND DATA FORMATS Full Tensor, 24-bit, GPS-synchronized Phoenix MTU-5A systems were deployed in tensor mode. At any one time, up to seven MT systems were in use, apart from spares on site. MT Equipment — MTU-5A System: e 5 channel Phoenix MTU-5A acquisition systems, with GPS antenna for synchronization 2 Metronix MFS-07 magnetic sensors (H, and H_); e 5 Pb-PbCI2 non-polarizing electrodes (Wolf, Hungary), per system; ¢ 200m AWG#12 cable (4x50m dipoles), per system; ¢ 1 Pentium Notebook Computer (calibration only — not in field operations); e 1 Yuasa gel/dryfit battery, 12V/32Ah; ¢ Connecting cables D.1 TECHNICAL SPECIFICATIONS MTU-5A (acquisition and processing unit): 24 bit digital resolution high and low frequency data simulateounsly recorded with separate filtering and gain characteristics. Removable CF Flash for data transfer to host computer and recording schedule setup. Internal GPS receiver; clock precision + 500ns to satellite reference; 12 parallel channels; L1 1575.42MHz; C/A code. Magnetic Sensors: H,, H, Metronix MSF-07 (0.001 to 50,000 Hz). Sensitivity 0.02 V/(nT*Hz) (f«32 Hz); 0.64 V/nT (f»32Hz). Electric Sensors: 4x50m dipoles (100m total), AWG #12 cables with Pb-PbCI2 non-polarizing electrodes. System Computer: Panasonic CF18 Pentium Notebook PC, with 2048Mb RAM and 60 Gbyte hard disk. Environmental: Power supply MTU-5A 1x12V 34Ah sealed lead-acid battery, 14 kg. Operating temperature: MTU-5A -20°C to +50°C MFS-07 -25 to +70°C Weights: MTU-5A 4.4kg MFS-07 5.5 kg GEOSYSTEM - WesternGeco EM D-1 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Equipment deployed at each site: Magnetic sensors used are MFS-07, in the table are listed the s/n. Sensor 000 or a blank field indicates no sensor present. MT site Date [Unit(s/n)|_Az(°) |Ex(m)| Ey (m) | Hx (s/n) | Hy (s/n) A001 12-Sep 1715 150 95 95 A002 8-Sep 1691 0 96 96 151 58 A002 11-Sep 1691 0 97 98 58 151 A003 12-Sep 1693 320 98 96 A004 12-Sep 1563 320 98 98 148 17 A006 12-Sep 1691 0 97 97 58 151 A007 8-Sep 1593 0 95 98 A007 11-Sep 1715 0 94 96 A008 8-Sep 1715 0 96 96 A008 11-Sep 1593 349 98 99 A009 7-Sep 1593 0 96 96 A010 7-Sep 1715 0 96 96 A011 7-Sep 1691 0 96 96 A012 5-Sep 1691 0 96 96 A013 11-Sep 1563 0 98 96 A014 10-Sep 1563 0 98 98 A015 11-Sep 1693 0 96 98 17 148 A016 3-Sep 1593 0 96 96 A017 5-Sep 1593 0 88 96 A018 5-Sep 1715 0 96 96 A019 10-Sep 1693 40 98 98 148 17 A020 3-Sep 1691 349 97 96 A021 2-Sep 1593 0 96 96 A022 2-Sep 1715 0 96 96 A023 3-Sep 1715 30 96 96 A024 29-Aug 1691 340 88 96 A025 30-Aug 1593 0 96 96 A026 1-Sep 1593 0 93 96 A027 1-Sep 1691 0 88 96 A028 1-Sep 1715 0 88 96 A029 2-Sep 1691 0 96 96 A030 30-Aug 1715 50 96 96 A031 29-Aug 1715 340 98 94 A032 29-Aug 1684 0 98 98 A032 8-Sep 1684 0 98 98 12 147 GEOSYSTEM - WesternGeco EM D-2 October 2009 City of Akutan Akutan MT 2009 survey Operational Report MT site Date _[Unit(s/n)| Az(°) |Ex(m)| Ey (m) | Hx (s/n) | Hy (s/n) A032 10-Sep 1684 0 98 98 5 147 A033 29-Aug 1593 0 96 96 12 147 A034 31-Aug 1593 0 96 96 A035 31-Aug 1715 0 96 96 A036 31-Aug 1691 0 96 96 A037 30-Aug 1691 50 96 96 A038 3-Sep 1693 0 98 98 148 17 A039 8-Sep 1563 0 90 90 A040 29-Aug 1563 40 100 100 58 151 A040 8-Sep 1693 0 100 100 148 7 A041 29-Aug 1693 0 100 99 148 17 A042 30-Aug 1693 0 96 96 17 148 A043 1-Sep 1563 0 98 98 A044 3-Sep 1563 0 98 98 A045 2-Sep 1693 0 98 98 7 148 A045 7-Sep 1693 20 98 100 148 7 A046 30-Aug 1563 0 95 96 A047 31-Aug 1563 0 97 100 A048 12-Sep 1685 0 100 100 149 141 A049 31-Aug 1693 30 90 100 17 148 A050 1-Sep 1693 0 98 98 148 17 A051 2-Sep 1563 40 100 100 A051 5-Sep 1563 20 100 100 A052 7-Sep 1563 0 98 98 A053 12-Sep 1593 0 97 97 GEOSYSTEM - WesternGeco EM D-3 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Calibration curves Prior to shipment of the equipment to the survey area, Metronix magnetic sensors were tested and checked by an engineer trained by Metronix GmbH. Example of a calibration curves from coil MFS07-005 is shown in Figure 7. Note that there are two sets of curves for each magnetic sensor, corresponding to the high and low frequency ranges (chopper on and off). 5 MFS-07 000 10' 10" e 5 8 7 2 2 z E a 107 —— Amplitude, Chopper ON 2] = = = Phase, Chopper ON ::| ———- Amplitude, Chopper OFF — Phase, Chopper OFF 10° 10° 10° 10° 10° 10° 10° 107 10° Frequency (Hz) Figure 7. Calibration curves for Metronix coils MFS07-005. For the Phoenix equipment (MTU-5A), a multi-frequency self-calibration is performed at the beginning of the survey. The resulting files contain a complete calibration of the instrument over its useful frequency range, independent of the mode of operation (e.g., line frequency, AC/DC coupling). Example of calibration curves for recorder unit MTU-5A #1563 is shown in Figure 8. GEOSYSTEM - WesternGeco EM D-4 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Cal Magnitude * cm = cm a) + cn os 180 12s 1.00 7 qenenteesecnen oaee ceed aeene nn oees epee sees ones ents tote ones nest enee enes Sten eens cons sens cate steD : o.7s{t" 0.50 0.28 oe 70 20 10 0 10 0 10 70 70 seats freeman an Gal Phase ae eee eae 180: 3s 90 “s i Ofpssrtunenseneaconessneonsonsonvenome mesnnecnnensensoennornecnnnnnnnmanenonensenetenssoe sees “48 -90) nass 5 10 10 10 10 20 20 10 10 10 Figure 8. MTU-5A #1563 calibration curve. D.2 MT DATA Data were normally archived in the following formats: 1. Binary format files containing acquisition information and time-series; 2. SEG-Electromagnetic Data Interchange (EDI) format containing impedances, apparent resistivity, phase, coherencies and tipper parameters. D.3 TIME SERIES Original field data were archived in acquisition information and time-series files in a binary format as written by the Phoenix acquisition program. Azimuths recorded in the time series header are referenced to geomagnetic North. All times series data are stored in a directory corresponding to the date of acquisition for combined files and in the subdirect of the MTU serial number for the individual hour files. Sensor files are archived on the processing HD. Individual files within the directory follow the convention: Combined times series files (hour files concatenated for high/low frequency recording mode). SSSSa.TdN where: SSSS_ = Site name (A) and 3 digits for site number a = run number (a= main prcessing file, b=chopper on for TS3 band) d = decimation level (S is no decimation) N =Sample rate: (2=24000, 3=2400 Hz, 4=150 Hz) GEOSYSTEM - WesternGeco EM D-5 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Time Series Hourly file designation Hourly time series files in sub directory of date in MTU serail number: SSSSDDDa.TdN where: SSSS_ = MTU serial number DDD = Date (MDD). Dates changes to next day part way through files. a = run number defined for the hourly file. Not consisnet as depends on when system started, SEE TABLE BELOW d = decimation level (S is no decimation) N =Sample rate: (2=24000, 3=2400 Hz, 4=150 Hz) AK time is Alaska time, UTC is GMT time. Time is start time (hour) of that hourly file. Yellow highlighted columns are data recorded with the magnetometer chopper amplifier off for high frequency recording. Bold highlight site names are stable magnetometer locations. Bold highlight hourly designations have magnetometers installed. Lower case letter indicate a partial hour recording. Day is listed date Day is listed date +1 Date ld site AK 9 #0 #4 12, «13° «14 0«15 | 16 «17 1 #19 «200 «210 «220 «6©230«600 Ss 2s HCG 06 07 yymmdd UTC 17 18 #19 2 21 22 2B 0 1 2 3 4 5 6 7 8 9 0 1 12. 13 14 15 090829 A024 a B E F G H I J K L M N 090829 A031 a B C OD G oH I J K L M N 0 P 090829 A032 a BHA B C OD G oH I J K L M N 0 P 090829 A033 o P QyA B C OD G oH 1 J eK L M N 0 P 090829 A040 o P Q RA B C OD G oH 1 J eK L M N 0 P 090829 A041 A B CHA B c oO G oH 1 J K Lo M N 0 P 090829 A048 ofA B C OD GoH 1 J eK L M N O P 090830 A025 a B E FG oH I JK L M N 090830 A030 q A B c uO G H ! J K L M N 0 P 090830 A032 q R S$ T UWA B C OD G oH 1 J eK L M N 0 P 090830 A037 a B c uO G H | J K L M N 0 P 090830 A042 q| A B c OD G oH 1 J K L M N 0 P 090830 A046 q R Ss T U A B en) G H | J K L M N 0 P 090830 A048 gq} A B c oO G osH | J K L M N 0 P 090831 A032 a BC F GoH 1 J K L M N 0 090831 A034 a BoC F G H | J K L oM N 0 090831 A035 a B c OD G H | J K tL M N 0 P 090831 A036 q Ry A B c OD G H | J K L M N 0 P 090831 A047 a BoC OD 6 H | J K LM N OP 090831 A048 aq sR S]A B c OD G H I J K L M N 0 P 090831 A049 q R Ss THA B c OD G H I J K LM N 0 P 090901 A026 p QqQya B c OD G H I J K tL M N 0 P 090901 A027 a B E FG oH ! JK L M N 090901 A028 a BC F G H | J K Lo oM N 0 090901 A032 Pp aq R § T Uy A B c OD G H I J K Lo M N 0 P 090901 A043 q A B c OD G H 1 J K L M N 0 P 090901 A048 q R S$ T U VA B C OD G oH 1 J eK L M N 0 P 090901 A050 q R Ss THA B c OD G H 1 J K Lo M N 0 P 090902 A021 A B a) G H | J K L M N 0 P GEOSYSTEM - WesternGeco EM D-6 October 2009 o7 15 05 (06 12. 13 14 03 1 Operational Report 02 10 19 20 21 22 2 0 O01 18 v7 Akutan MT 2009 survey City of Akutan 2 ttqeodqdqicvoectceaeaeaedisoceatcaeaeaeetiacatcvoaeaeatcae aqaidto qietqaqacqcdieacacacaatce =< oatct _ 2 a> > cla no>ons eoOumool|to wou o cao> Blomuo mooaecnd> co +> zal es 23 |e «ds «> oweuol o w wool cos slo owul sacers a> 2Qa BK e or o> oa wt < a ac & pil« ow Oor er 228 o ow an F °o a o 8 ® Bb co =o oo = & oc c oc a oa oO a a oc ao ao sax x ee o oc co od + a 7 a o i oo so o = oc o c o ¥e <5 ces} |SSSSPSSSSSSSRLSLSHSSSSSSSSSSSSSSSSSSSESSSISSRLESRSSEsgRe 2 3 ss 3 SesSissessggs BSsisssssssi8ssssgs 2% S222 SSF E22 CE SE2 FEES SF2 CECA eC CCCI LC e2ZeAZe2ee22R¢222ee 772 e| Zissssesiggegsgesisssessslssssssslsseesesleceslssseszeslseesees S| FESS SSeS SSS SS SSS SS SSS SSSSSSSSSSS SESS ees eeeeeeseeee2 28 a € S SS BASBAS BBS SSSSSSSSSSSSSSSSSSSSSsSSSSSSSaSSSSSSSISSSSSSSSSESSSSSESSSS October 2009 D-7 GEOSYSTEM - WesternGeco EM City of Akutan Akutan MT 2009 survey Operational Report Time Series File Format Decimated time series (decimated during processing) retain the same site and run-related prefix convention, but the last letter in the extension “*.TdN” is changed as follows: Band name Sampling frequency Derived from (Hz) Ta4 75.0000000 Band 4 Tb4 37.5000000 Band 4 Tc4 18.7500000 Band 4 Td4 9.3750000 Band 4 Te4 4.6875000 Band 4 Tf4 2.3437500 Band 4 Tg4 1.1718750 Band 4 Th4 0.5859375 Band 4 Ti4 0.29296875 Band 4 Ti4 0.146484375 Band 4 Tk4 0.073242188 Band 4 Time series files consist of records containing time series data, written chronologically from the time of the first sample in the record. Record lengths within a single file may vary. Each record consists of a tag followed by time series data. Figure 9 illustrates the file format graphically. The time series data is stored in 24-bit two’s complement format, three bytes per sample, least significant byte first. A scanis a set of samples, one from each channel, taken simultaneously. A complete scan from one sample time is stored consecutively in order of channel number. Recordo Record: Tago Scano Sean: oe Scann Tagi Seano Scan: 9a careening er Ch» Chi Ch Cho ChiCh2 «. Cho Chi Cha Cho Chi Ch2 Chr — Sa Geomealny cin ty iy desi samples t ‘Simultaneous c second 0 = 1 byte Ch = Channel Figure 9. A graphical representation of the time series file format. The scans within one record span either one second (Bands 3, 4, and 5) or 0.1 second (Band 2). Records always begin on a UTC second, but not necessarily on consecutive UTC seconds. (Channels are numbered starting at 1, not 0.) Scans are stored in order of sample time. The first scan in a record always starts exactly on a UTC second, and the scan rate is always an exact integer multiple of 1Hz. GEOSYSTEM - WesternGeco EM D-8 October 2009 City of Akutan Akutan MT 2009 survey Operational Report TIME SERIES: TAG FORMAT The tag format may vary depending on instrument firmware, but only one tag format is used in any one file. Currently, tags are 32 bytes long in TSB files. Table 3 summarizes the byte assignments within the tags, and the paragraphs that follow provide additional detail. Bytes 10-11. The number of scans in the record. Except in TS2 files, every record contains 1s of data, so this 16- bit integer is also the sample rate in Hz. (TS2 records contain 0.1s of data.) Byte 13. In TSB files, this byte contains the tag length in bytes (currently 32). In TSL and TSH files, this byte contains the code 0, indicating a 16-byte tag length. Byte 14. The instrument status code values are explained in Table 4. Byte 15. Saturation flags. Each bit corresponds to a different channel (bit 0 for channel 1, bit 1 for channel 2, etc.). A bit's value will be 1 if either the common mode or differential mode input voltage limit is exceeded in any sample. Byte 16. This byte is reserved for future use to identify different tag formats or different sample formats, such as floating point or compressed format. The value is currently 0. Byte 17. The sample length in bytes, currently 3. Future changes in sample formats (32-bit integer or floating point, for example) may cause this value to change. Bytes 18-19. The sample rate (per unit time as specified by Byte 20). For the range of possible values, see Table 5. Byte 20. Time unit of the sample rate. The current range of values is shown in Table 5. Other values may be defined in the future. Byte 21. Clock status. This byte reflects the status of the clock at the time the record is taken. A value of 4 indicates that the clock was locked to GPS. A value of 3 indicates that the time is based on the crystal oscillator initialized by GPS. Bytes 22-25. Clock error in ps. The value will be 0 unless GPS lock has been lost and reacquired. Recovery from GPS dropout (re-synchronization of the crystal oscillator) can take up to 20min. During this time, the difference between the recorded sample time (bytes 0-7) and the actual sample time is recorded as clock error. This value is a 32-bit two’s complement integer, positive if the sample is late, negative if it is early. Table 3. Summary of tag byte assignments. Byte Meaning Byte Meaning 0-7 UTC time of first scan in the record. 12 number of channels per scan 0 second 13 tag length (TSB) or tag length code (TSH, TSL) 1 minute 14 status code 2 hour 15 bit-wise saturation flags reserved for future indication of different tag and/or 3 day 16 sample formats 4 month 17 sample length in bytes 5 year (last 2 digits) 18-19 sample rate (in units defined by byte 20) 6 day of week 20 units of sample rate 7 century 21 clock status instrument serial number (16-bit 5 8-9 integer) 22-25 clock error in us number of scans in the record (16-bit : 10-11 integer) 26-31 reserved; must be 0 GEOSYSTEM - WesternGeco EM D-9 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Table 4. Tag byte 14 status codes. (Value |Meaning 0 _|normal completion internal error reserved saturation of front-end board analog circuits internal error in front-end board digital signal processor (DSP) internal error processor timed out without receiving data from front-end board! DSP 7__|internal error 8 __|internal error | [WIN |= o>) Table 5. Tag Byte 20, Sample rate units (Value [Unit Q__|second (Hz) 1 minute 2 __|hour 3 day D.4 EDI FILES The processed MT data are stored in standard EDI files on the final CD, a copy of which is provided with each copy of the report. Azimuths in the EDI files are referenced to geographic North. The EDI file naming convention was as follows: Annn.£D! here: nnn. where: A = Survey area: Akutan nnn = Station number identification The SEG MT/EMAP Data Interchange Standard is described in Wight, 1988. Since this is an extremely lengthy standard (91 pages), the reader is referred to that document for details. GEOSYSTEM - WesternGeco EM D-10 October 2009 City of Akutan Akutan MT 2009 survey Operational Report APPENDIX E MT PARAMETERS Overview The magnetotelluric method is a means of determining the resistivity distribution of the Earth through the measurement of time varying electric and magnetic fields at the surface. At each MT site, data from five channels are recorded as a function of time, which is referred to as time series. These channels are indicated in the following figure, and correspond to three orthogonal magnetic field components (designated H,, H,, and H,), and two horizontal electric field components (designated E, and E,). Note that a right-hand coordinate system is used and zis positive downwards. Ex Hz Figure 10. Coordinate axes and component identifications for 5-component MT site. As an electromagnetic method, magnetotelluric depends on Maxwell's law stating that a time- varying magnetic field induces an electric field in a conductor. The source fields are the time- varying horizontal magnetic fields (H, and H,), which are generated by two distinct phenomena. The high frequency source fields, greater than 1Hz, are generated by lightning discharges of distant electrical storms. The low frequency source fields are generated by the interaction of charged particles, solar wind, with the earth’s ionosphere. The output of the source fields convolved with the Earth consists of the horizontal electric field (E,, and E,) and the vertical magnetic field (H.). Thus, ideally, the electrical nature of the Earth (i.e. the impedance) can be determined through the transfer function of the measured input and output signals. 4 in y out E, ne EARTI 7 He GEOSYSTEM - WesternGeco EM E-11 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Measured quantities The actual parameters measured in the field are the time-varying voltage outputs of the electric and magnetic field sensors: E,, E,, H,, H,, and H,. Data were recorded in 3 bands, 2400 Hz, 150 Hz, and 15 Hz sample rates. Computed functions The measured parameters, the electric and magnetic field values, are transformed into the frequency domain using FFT procedures, and convolved with the sensor responses to give the complex values of electric and magnetic fields at specific frequencies. The resulting Fourier-transformed spectral estimates are combined into a spectral crosspower matrix relating all of the measured electromagnetic fields at discrete frequency values. If the spectral values of two channels at frequency f in the channel bounded by frequencies between f,,,and f,,, are A and B (complex numbers), then 1 j+tm (AG) AAD) = sy DAA =(4e 4G) +1 Fm define the autopower 4,4j; ;and (A(f,).BU,)) = said A,B; =(4,B;) 2m +1 Fm define the crosspower A,B, ,where the * indicates the complex conjugate. The impedance tensor is calculated directly from the crosspower matrix, via relationships of the form )eH. EH; _ DEH )E.H;( “eC )H | )HLH( )H,H,{ * < eH Wap atel Pena eens os Ly * = The relationships between the five measured components at each site are contained in the impedance tensor (Z,) and the tipper transfer function (T,), expressed by: E,=Z,H, +Z,H, E= ZH, +Z,H, H, = TH, + TH The impedance tensor and the crosspower matrix are used to derive more practical parameters for interpretation and data quality assessment. Data interpretation parameters The interpretation parameters are calculated using the standard definitions of Vozoff (1991), and are described here in simplified form: Apparent Resistivity - scaled magnitude of the ratio of each orthogonal E and H pair, with associated variances, i.e. =a P; ia GEOSYSTEM - WesternGeco EM E-12 October 2009 City of Akutan Akutan MT 2009 survey Operational Report Impedance Phase - impedance phase of each orthogonal E and H pair, with associated variances. Impedance Rotation - presents rotation direction of Z,, (i.e. it can be a fixed, user-specified rotation angle, or that defined as impedance strike). Impedance Strike (6) - angle which minimizes |Z,,(6)|° + |Z,()|°. In an ideal 2-D environment, one component will be parallel to strike (transverse electric, or TE mode), and the other will be perpendicular to strike (transverse magnetic, or TM mode). Tipper Strike - direction which maximizes the cross power of horizontal and vertical magnetic field components + 90 degrees. Tipper Magnitude — magnitude of the vertical magnetic field with respect to the total horizontal magnetic field. Tipper = SOQRT(|T,|’ + |T,|’) Impedance Skew - impedance tensor ratio, 3-D indicator, invariant with rotation. ZotZyl/l2u-4nl Impedance Ellipticity - impedance tensor ratio, 3-D indicator, dependent upon rotation. |Z,,40)-Z,,(8)|/|Z,,(8)+Z,,(8)| GEOSYSTEM - WesternGeco EM E-13 October 2009 City of Akutan Akutan MT 2009 survey Operational Report APPENDIX F MT DATA PLOTS The MT curves are plotted in this Appendix without any static shift correction applied. All data are rotated to 0°. GEOSYSTEM - WesternGeco EM F-1 October 2009 WesternGeco Rotation: 0.0° Sounding A001 WesternGeco 7=0:0020 r= H : 2 2 : HAD fF] — fH} : : : : : T=0.00a1 Fe Beare T= 3750F2 T= T=0.0051 Fe 8 Baa re T= 508r2 720.7027 He a 8818 T=0.0870 Fz & T= 8268. Fe T= O44 He T= oa2re 8 |(8 |(8|[8 8|ell@ T=090c5 He 720.1306 Fz BB] Bl BS 7=0.0084 Fe T=O0T25 Fe = Zxy Impedance = Zxx Impedance Sounding A\ Finoxy o Rhovx f Phasexy ¢ PhaseYX — 8 Z strike '@ Z rotation © Z skew sual 10% (w-wyo) oyy “ddy (Bap) aseud (Bap) ynwizy “ued ‘UaWig = Impedance Strike 10° 10" 10? 10° Period (sec) to! © Zellip. ul WesternGeco T= 11a Fe T=0.1202 Fe T=O0Taa He Sounding A002 T= BOT REF T=TO8Ra Fe T=TeeSFe T= Sere Ta 185he =ONTAO Fe 7=0.0206 Fe 7=0.0020 Hz © @ eP GR BR 7=0.0320 Fe T=0.0051 Fe & @ &P GR eR T=00540 Re 7=00051 Fz WesternGeco T= 8258. He Ta Sasa re T= 730 he 720.7027 Hz T=00824 Fe 7=00080 Fz = Zxy Impedance = Zxx Impedance Sounding A002 (w-wyo) oyy ‘ddy (Sap) eseyg (Bap) ynwizy ' ! x , = j i 7 c +o- o & to 3 x § Bp nanan BR nn nctencnnn 4 i 5 gs . ' c a N « Ju Ju i i pe . 2 S$ 2 & *®% “wed "uawIG © Zellip. 3 Zskew i = Impedance Strike 10° 10? 10? 10° Period (sec) 10° 10? 10 104 ¢ g 8 2 2 2 i 883 + H Fa Fd H Fd 8 Si. : s e F 55° 2° ie ig iB Is lg § 2 8 | me iS 8 sae 3 ls F is s iS 3 < : : CD k R BES < ECR) R FE R E 2 il ere 2 y = 9 aA 5 x x f : > N sa y a a iy i 4 i: i is iy a Bl 7 Fl H B B B B i 8 E g H TORQTH@NHSI Qi MHS} i a ©) fg $3 Teere = SHIRCHIRGAIECaIEG o) 6) & $e Le @ = ©) za) Q}O|@ zal WesternGeco ©) oD =a S : & fe 3 7 . g 3 o % So < 7 < 2 2 oO % oO 2 ees 3 a a a 0 2 3 a 38 26 a ! 1 1 x ' x : 3 z 3 2 x a 2 7 3 i x , i i A c pO o = Q +o- a Be i ge ro 53 F i i 2 | 88 3 i i os @ & N gs é : a N $3 i : ge ot te . 10° 10 (w-wyo) oyy “ddy (Bap) aseyd (Bap) ynwizy “Wed “UaWIG (w-wyo) oyy ‘ddy (Bap) eseyd (Bap) yynwizy “Wed “UsWIG = Zxx Impedance = Impedance Strike 10? 10! 10° 10! 10? 10° Period (sec) @ Zellp. 10° 104 1B Z skew T= 1196 Fe O]|O||O||O||e A|O|2|[e||e o|(a|[e@][e|[e Te 14h = Impedance Strike Sounding A006 Z TaT65SEFe T2307 EEF Sounding A007 T=OST Fe T= Bae Fe i T=712.50Fe Ta 4453 He T= 1868 re T= 18a re 7=0,1068 Fe T= 466 rz T=0-4440 Fe 7=0.0040 Fz @Hl[l[a]/@ 7=004T2 Fz T=ORTe Re T=00a63 Fe T=O.0036 Fe = Zxy Impedance = Zxx Impedance T=OTasore Toonz Fe T=O0Teo Fe TODO He = Zxy Impedance = Zxx Impedance = Impedance Strike | | | | 720.0320 Fe T=0.00s3 Fz T=0.0664 Fe 7=0.0064 Fe O||alle GHIGHIGHIO Sa7a re T= 466 He Ta 1.14 Fe = T= 4770. Fe T= 4770. Fe Ta=Ta1 aoe T= 11.96 Fe T=0.1076 Re rs || | Q]|@H]|QH]] HI] SB | Fd ie i 2 # e 2, H E le jt [—, y lz | 8 E 5 e e EI fe g Ei fs S| * Py. s E e 9 : : Ie is iz ig g q iy e iy ig is ie } § Y ry * P|. P| x a|* P | 3. . 3 = 3s | | | | | | | 5 | | qe 2 qe | oD £ { z * = 9° qe ° ® oo oF {2 3 is 3 3 | 125 a8 a a | | y ' % qe 1 x i- \ 3 . ' i i i ale ‘ Liéleds | S qc fo 0 nq 3 « r N | ge = > . b8 Be ‘ . G3 x 5 8 ‘. : 53 ; j i ifs | 58 j Pee 85 \s i i 7 i : $s . sé - i+ EL & 7" 2 (w-wyo) oyy “ddy (Bap) aseud (Bap) yinwizy “we “UaWIg (w-wyo) oyy “ddy (Bap) eseyq (6ep) ynwizy “ued “UaWuid WesternGeco ° £ | £ g re) ye x s — i [—, ef, Fd = 3 sss 2 iz 3 st iz 88s | S a e Fe 4 3 s gs? 3 is Rg 5 5 a8 2] % Ig ie = 2 iS g B38 S is 3 = 3 333 < 7 " Le ie ie ie ees < Fs " le iF EES D i F y y : os 2 S P|. y eee 5 See £|* * x REE 2 1 1 2 ond 3 F [> H es [—, i (— H 3 iz iz : i is i oO}. S ¥ Ns is iS i iS 9 i st i i E E ie Ie 4 a Is I Ie Ie Je Is iz ie >: H : Ef, co : ee FH Fa : : iz KR] ¥ 1B 3 iE ss ig is 3 » = is is Ie = 3 ig ie Ei Q Ie Ie Hk R Ie Ie Ie iq Pr * : x * x ® | L_ | Fa je x e E ~ je * jz je jz it je iz ze | x ie le ie ie i fe q i" I: q i fe | 2 EE x é * é : jt ~ e Fa 2 ra je é = 2 x iy 8 ie is TOIOHOEG | OT@} IOPOES HG IOI@} e je eS * IS S uy e iS is I~ ie S ie s s|* * x A Z 3 . . 3 3 | 2 o a 8 % 8 % < 1-= <x qe aD D £ £ 9 qe sc] 7 2 3 5 5 a - a -~ | 72 72 2 o 2 8 a3 a7 3B) 3 3) ° 5 ° 5 re a) | ' s 9 ' x ° 7 \ P| x i = 7 x i Ste | 2 a N & 3 N sI% « Lo o e ° = o nqe | 8 i . ge i . s § oo § ° . X § . S 5 5 F j : fy, | 5s g 3 ie 5 « c N N Bs = N N 3S i“ i“ 2 a $2 Le . a é sé i i i * 2 %& % | (Bap) eseyg (Bap) ynwizy “ue “Uawig (w-wyo) oyy “ddy (Bap) aseyg (Bp) ynwizy “wueg “UaWIg WesternGeco Rotation: 0.0° Sounding A010 WesternGeco T= 16758 T= a5ore L T0760 Re T=0.1076 Fz T=o0T0s Fe T3077 Fe T= 15232 T=0.0160 Fe T= 541.50 T= 25.00 He T= 228 re T= 147 Fe T=01648 Fe Ta02a0a Fe T0246 He T=0.0016 Fz T=0.0026 Fe T= 3762. Fe T= S215 Fe T= amare Ta0aaaa Fe T=00aTa re 7=0,0040 Fz T= Gat He T= oa16 re T= Seanez T0722 re 7=0,0664 Fz T=00063 Fe = Zxy Impedance = Zxx Impedance Tino ftnovx } Phasexy ¢ PhaseYX — 1 as pepansnsasass: oF % (ww-wwyo) oyy ‘ddy (Sap) eseud (Bap) ynwizy ° “ue “uaWIG = Impedance Strike 10° 10° 10? 10° Period (sec) tot WesternGeco Rotation: 0.0° Sounding A011 WesternGeco waare TaT1053z T= T=0.8789 re T=01465 Fz T=0.0160 Fz T= 218.04 Fe Ta 47 Fe T= 147 He T=0.1877 Fe T=00263 Fe T= 387.30 Fe T= Bada He T= 24a He T=02565 re T=O0aTe He 7=00026 Fe 7=0.0040 Fz T= 60665 T= 3750r2 T= 380 He T=O37Sa Re T=0.0641 Fe T=0.0063 Fz T= 4770. Fe T= 660 Fe Basre = T0722 Ae T=00838 Fe T0010 re = Zxy Impedance = Zxx Impedance Sounding A011 nT 4 PhacoxY PhaseYX — 8 Zstrke '® Z rotation Ju % * (w-wyo) oyy “ddy 8 (Bap) aseug (Bap) ynwizy “We, “UdWIG @ Zellip. 1B Zskew = Impedance Strike ul aut . 107 10° 10! 10 10° Period (sec) 10° 107 104 WesternGeco 2 2 a a i a i 7 i B85 © a i a a a | = i : 5 q fs fs ees < i fi fi Ei B ga5 2 P P ack a], * > Y - Ets 3 iL ; * * Rae S * ; pee 3 7 x re 3 * : Te 5 — 3 iB lz Le 2 i i 3 ! 3 i Le a Lt o : 5 ie R i e B Ei e i i a e ie le Ie is is Is : le Ie Is ie iz ie i ie Hl 2 H 3 2 i 2 2 i i i Re i i E E Hy P E E E Fa 2 i 2 i i iB Ed 2 i A iz F E 4 RE R Fi E FE es & Os RE E RE , * . . t " | > x x x # ’ | i 1 2 2 2 iz | 8 A 8 fs A fg B fe | Fi B Fl A F ; | 3 e S Ee fe S | 8 fe > 5 8 E | € q 2 is Ie fe iq ie e is f ie e g fe | 3|* : i 5 ie = fg 3 x * a \ 2 * x * : \ | i 2 3 Js 3 % : a t £ 2 2 % 3 2 47 2 qa 2 5 5 ao - no ~ 72 qe i Wdog oo i 723 73 3 8 25 23 728 qe \ a 7° gh : x $f 81s i s : #]¢ Je ed, E tpt HE | : if 8 sf i? és § i 3 F BE gle (58 i iy: | s = NF N gE N nq” | 2 i = fi a 22 . a | e "e 2 | e 2 | (w-wyo) oyy ‘ddy (Gap) aseug (Bap) yjnwizy “wed ‘UaWIG (w-wyo) oyy ‘ddy (Bap) aseyd (Bap) yinwizy “Wed UsWIG | He | ° g ang segs 5 0 2 i Ls iz 885 + e lz fe é é ego x e iS 3 e g 55% < i : EQ fF fe BE3 F C8): ie e e EER o 4 a | * ey o| | | « sae £ Bae £ See vv one TU ou c ce iS i i y i kt 3 Et Fd 2 D| RY By. 2B E R o 5 E E 8 4 q S| ig Ie Iz Ie Taare 7=00051 Fz T= Tare Tones Fe T= a6 Fe ToOaaaO Fe T=OOTeT Fa T=O.0080 FE o 0) 8 6 [8 [8/8 /& 7=00601 He 7=0.0383 Fe r m T=0.0040F2 T=0.0028 Fz T= 350.98 He T= B0as2 re T= 18.70 he T= 1.902 7=0,0066 Fe T= 55450 Fz Ta a8 Fe T=01053 Fe T=0.01s6 re T=0.7807 Fe 7=0,0084 Fe O| O 88 8/8 [SSIs _—_ ©) = @) FS C a ae WesternGeco © =r © Ta ©) () = rar + 10 es = | % 2 Ie | | 2 qe 2 e | oo D < i | 2 j, | 5 }e ; ¢€ ba < 5 2 3 6 a a 9 Ye {23 moo 73 | _B ans > = 2S | eae nena 725 Pere eee Cee core Ce COT ace et eee ee ee # Je ' | z g | 8 : dx | ; i ‘ éls i i ile | Q « to o e ial 8 i ei o 7 8s po- 8 5 ge % : ee i zx 53 3 i i ie [83 3 i bye gs = & N N gs = g2 I . : ° 33 i . : ° | e 2 *e % . | | (w-wyo) oyy ‘ddy (Bap) aseyg (Bap) ynwizy “uueY “UdWIG (w-wyo) oyy ‘ddy (Bap) aseud (Bap) ynwizy “Wed ‘UaWIg WesternGeco Rotation: 0.0° Sounding A016 7 9 WesternGeco Sounding A016 E ee Tae TaTESOR Toa SFE ei E ‘ S| s * * x ° 2 a & < T= 203.32 Hz f= 117.19 Hz T= 67.38 Hz T= 37.50 Hz T= 22.80 Hz P Rnoxy Rhovx = T=TaSEFE Taare 1 3aFe T=SaeFe ES Fe==" x x x x x a | z 2 | a ToT T=OSTGEF ToOBSEaFe TOaCEF TOT TE | £ z z : z : me TONER TOTO T=ODeeT Re T=OaTar T=OnzGOTe 3 = x = > : 2 € 3 £ Ni < ToODTear T=OOTOEFE TODO T=O OIF TOOT Fe E os a ¢ 2 T=o Dear a = Zxy Impedance 0 Zskew = @ Zellip. = Zxx Impedance ‘ mn ml a mi a n = Impedance Strike 104 103 10% 10° 10° 10? 10° simp Period (sec) WesternGeco s Rotation: 0.0° ounding A017 7 9 WesternGeco Sounding A017 App. Rho (ohm-m) Phase (deg) Azimuth (deg) Dimen. Parm. % ©) © © DZskew © Zellip. m au m1 10 10" 107 10° DP] CP || || || |) eB a2 || || SRB ]/RV I eR 7=0.9933 Hz 720.6363 Hz 1=0. = — 1=0. — RI BA|BIAl@ Go C — = Zxy Impedance = Zxx Impedance = Impedance Strike | sez sae © By z if Fy iE A 228s 2 ~ &— . & et ie je jE B25 | S|. P| S| % ey] iS E E Ba 8 3° ss 3 «fe . . 3338 | ; << fe fe : S| i i ges < a fe ls 5 8 i ees | oo I: ¥ y e in - fs D i i P P P Bak = SRE & SRE 3 tae 9 oe c | 23 2 2 i st i #3 3 ~ ~ iz i ie Fy | 8 ae al, | RT g is a a g \ 2 . a E | . ie : : iS S| is Fe ; Le iS ie a ' : ; P P P P ; ) | x x Tizsore T= 487 Fe T=05850 Re T= LY ® aasore & ——l | T=0.1076 Fe SS & SSBB © QDI Ly S aa & ——-4 — Ne) e e &[6 ie je Fa Fa Fa 2 x 2 Fa Fa Fa 2 8 :. | | i g e F a]. i Pt u \ iB fe E a | | | Co) 2 | So % ees ceeds qe 2 ri: 2 2 5 I% 7 Eu case Muetee Mee ste seca a qe c = < 5 =} 3 2 a Je Ot qe | | Ie 3 Le i238 | "a 2 3 }e 8 | 7 Bp Pr gers “a ' IN AN) IL ae IIL | J’ | ; : qe ' x . g 3 z 2 7 ; i ‘ tts j l : th c jo oF ngr 8 . eH jo o : 38 - z gh : g3 z § : & + é 4% 55 5 i BE bye [88 i i 8 x4" OS € a N FI N gs c a N N (22 pe fe = ft o s2 H fe = . a | | rr e e 2 | (w-wyo) oyy ‘ddy (Bap) aseug (Bap) ynwizy “uued “UdWIG (w-wyo) oyy ‘ddy (Bap) aseud (Bap) yjnwizy “uued “UsWig | “| | WesternGeco Sounding A020 WesternGeco Rotation: 0.0° Sounding A020 2 2 = eek ie ef. Fd eT. 2 885 x a le ie jz Hy Et 885 / By F E E E ga3 8 E : F Fi E E nut fe 5 4 e e EES < i @ Le Ie | ie e ie EES y 3x8 > i . . i ree NRE £ il Ans& a wae < it 8, i i i a i i i fd i i * ie} Ss 8 8 e o : Rg 8 F E E . S| a s 8 i fs OVOPO|] OIE} P ||D PIP] SP} Ld} Ld i 2 2 Ef ef, z lz : 2 : 2 : AIOHOPOHONE] P | ODD Da} je? 2 je ie . rd Py Fa je = Fa é é |e RT) EN ELE F E : i i : : : i P f Fe i fi k R $ q f GE | Ey i R s|) A ' 3 aN Je g Je D £ je | 3 Je 3 5 qe ° 7 {23 12 2 _3 « 728 qe 1 Js 1 x x 3 . é i $12 3 $17, bo 0 ngr 2 to nae % : gs % i § so 5 ans Ee : zit i af ere a3 i F ay? la na "Eh ° se re L s = e 2 (w-wyo) oyy “ddy (Gap) aseyg (Gap) yjnwizy “Wued “UdWIG (w-wyo) oyy ‘ddy (Gap) aseyg (6ap) ynuizy “Weg “USWIG Period (sec) Taare T=00aTa He 7=0.0040 Fz T= TAT Fe 700760 He T=0.0016 Fe oe) G)E\|8 = Zxy Impedance = Zxx Impedance = Impedance Strike = Zxy Impedance = Zxx Impedance = Impedance Strike Sounding A022 Sounding A023 T= 30551 Hz T= 2B re T= 225 T=0.0260 Fe FI B|B SB T=0,0026 Fe Ta Tat4 re 720.0664 Fe | S| @) & 4 & T=0.0063 Fz LIE IE §||8||8 T= S402 Fe T= 2057 Fe je jz 2 Fa je i 2 je jz Ea & OF [SD] @ OFLA] Le q S| ie le Ie ie e IS | Ie | je Fa Fa jt § F 2 F é i A iE g]* " ails 8 g|- 1 8 ey Hie 8 E 1TPHON@HS aoa} 1@H@H®]H SII ies} 8 y - y ii P 2 - g 3 = = 1" 1 7 | a % i % | : [3 Je = 7 | oe 2 PE 2 S| Bea ? 3 2 ' 5 O° ‘ a e a ye | oF 23 2 3 rr qe 3B .3 3 S & L-- i qe 8 ge a *e ' ak qe | ' ' x a8 | an | 5 SS — te G i a i ie | 2 « 7 8. c foe nant o N 8s bo Bo ro z sf 7 os ge 55 5 2 | 58 i i i ye BE = gs = ' a N FE N | sé r 22 i i te i te aE 8 | ® 2 % 2 & 8 8 2 (w-wyo) oyy “ddy (Bap) eseyg (Sap) yynwizy “We “UdWIG (w-wyo) oyy “ddy (Bap) aseyd (Sap) ynwizy “ued “UaWid | WesternGeco Rotation: 0.0° Sounding A024 WesternGeco Oofoloe|[x} CLOHOHONSN! OVOVOHolle |x} OOfololele} OPOFofololle] = Zxy Impedance = Zxx Impedance Sounding A024 Tino prove PPraseyx = } Pracoxy 0 Zstrke ‘© Z rotation (w-wyo) oyy ‘ddy (Bap) aseug (6ep) ynwizy “Weg “UdWIG = Impedance Strike 10° 0! 10? 10" Period (sec) WesternGeco Rotation: 0.0° Sounding A025 WesternGeco 7=0.0020 Fz T=0.0031 Fz OLOFOOTE| OONO]e |e} OFOHO|O le lae Ooofolale OLOLOTOITe T=0005T Fz = Zxy Impedance = Zxx Impedance Sounding A025 PPraseYx } Pracoxy o Zstrke '® Z rotation i i * (w-wyo) oyy “ddy = Impedance Strike 10 Period (sec) © Zelip. wi 10° 10" 8 2 skew 104 WesternGeco Sounding A026 WesternGeco = Zxy Impedance = Zxx Impedance = Impedance Strike SUSU EET VAI VASES RTE COLI! iz iz i iH it [— i OlOKoTOlelek f fs R R R 2 2 4 a a 2 OHOPOHE LEE! re Q ie | * S| * ie ie Oloforelelel STOTONO TS ie| T=0.0016 Hz Sounding A026 Rotation: 0.0° 1 x 3 2 a bo % 3 2 a i“ © Zstrke ‘© Z rotation (w-wyo) oyy “‘ddy (Bap) aseyg (Bap) yinwizy suueg “uaWIg 10° 10? 10° 10° g 3 a 10° 107 10 WesternGeco Rotation: 0.0° Sounding A027 & WesternGeco BeTare ‘Ba68. Hz T= 7a0Fe T=07507 Fe T=0.0664 Fe & 2 2 jz je 4 ; : : i e AIOTO | Shek MPEP EAT OOOO! Q@LOLO |e} id E je = i SOOO OP] 7=0:0066 Fz = Zxy Impedance = Zxx Impedance Sounding A027 Tino f phovx $ Phasexy ¢ Phasevx — 8 Z strike © Z rotation % "e % (w-wiyo) o4y "ddy 10! (Bap) eseyg (Bap) ynwizy “Weg “Uawig © Zellip. 8 Z skew = Impedance Strike WO ea (sec) 10 Peri WesternGeco App. Rho (ohm-m) Phase (deg) Azimuth (deg) Dimen. Parm. Rotation: 0.0° Sounding A028 . 9 WesternGeco Sounding A028 — T= BEEF T= a77O Fe sa T=TTESOFE T=oSEST Fe E z z z z , s °° 2 a & < T= 219.14 Hz T= 12129 Hz T= 67.87 Hz T= 39.26 T= 22.89 Hz TTT S6Fe T= 707 1 aaT Fe Es = Taare 3 2 2 g T= 21 he T=0.8769 Az 7=0.5859 Hz T=0.3571 Hz 7=0.2403 _ TOTS TOTOSaHe TOD6OT Fe TOOaTa Re TONG 2 Zz s x « . * x S £ x < TORT T=ODTOaFe TODO Fe 7-000 TODO E os a ¢ 5 £ a —— = Zxy Impedance OZskew © Zellip. 2Zxx Impedance “ ul 7 / . : = a = Impedance Strike 104 10° 10? 101 10° 10° 10? 108 . Period (sec) WesternGeco Ss Rotation: 0.0° ounding A029 . 9 WesternGeco Sounding A029 P. © @ ‘© Z rotation Period (sec) TREE T= aOR EEE — 7 = 7 = = Sas 7 =" ETRE aa : CHTOATCATCHIC, g RRovx 7 = Taare es ae TOaTeaFe &Y KY O}|@ TOS Toa Fe OTE Te @ © a T=00469 He T=0.0a1S He T=00051 Hz T=0.0031 Fe T=00aTa re = Zxy Impedance = Zxx Impedance = Impedance Strike T= 1196 Fe T= 127 Fe TaO.1648 Fe T=O0TeO re T=0.0016 Fe = Zxy Impedance = Zxx Impedance = Impedance Strike Sounding pv S TaTaeaa Fe ® : T= o3a Fe ~ : T=OSTaER ® T=OD6GA Fe & T=ODTaETe = Zxy Impedance = Zxx Impedance = Impedance Strike ee A031 % 7 TEE TaT he T= T=0540a re T=0.0664 Fe T=0,0066 Fe T= 49.50 Fe | * +z ae ET. ii ef : : : 3 2 2 PIOIOIO|P| eI BI@I@H@llesilael | 3 @® oe) Y 2S S B UO | S| ©) T=0.1053 Re T=o0T0s rz WesternGeco Qs Y eS S ® aS WesternGeco R&S es) a el (9) 8 So . = | oO oO | So 4% So % < . < = . 2 > % 2g qe 2 S 3 3 2 te 7 i) .o 2 72 3 "3B 3 38 72 ee ' Is ' % ' x : 4 x : 3 5 i i 21% é 2 = bo o Nar 2 o ~ ge re . ge Oo z § Os x 5 § 5 i 3 i Je 55 i % | BE = a N N es a | 3 2 fo jo . a 22 I be | % % % % eo 8 | ~ = me ~ ~ = | (w-wyo) oyy “ddy (Bap) aseyd (6ap) yynwizy “WE “UdIG (w-wyo) oyy “ddy (Bap) aseud (6p) yynwizy “ued “UaWuIg WesternGeco Rotation: 0.0° Sounding A032 WesternGeco & T= 258.08 Fe T= 1846 He T= 1902 T=02220 He 7=0.0206 Hz Sire T= 3852 T= 28.71 He T= 28ere TaOsaas re 7=0.0320 Fz T=0,0020 Fe 7-005 Fe T= 71250he T= 4900 Fe T= 487 He T=00081 Fz Bea He T= 4770. He T= T= Tear T=0.7507 Fe T=0.0824 Fe 7=0,0080 Fz T= 8208, Ta 1401 Fz © (G)@)(8)[8 38/882 T= 11.962 T= 127 Fe 7=01386 rz T=0072a rz Zxy Impedance Zxx Impedance Sounding A032 T™ FP Anoxy § RhovK — } Phasexy ¢ PhaseYX — © Zstrike '® Z rotation bathe (Se oceeocen i en PAAR | © Zellip. ‘© Z skew (ww-wyo) oyy ‘ddy (Bap) eseyg 8 (Bap) yynwizy “ue ‘uawig = Impedance Strike 107 10° 10! 10? 108 Period (sec) 10? 10°3 104 WesternGeco e oO 2 Fd ie ie $36 3 fe 5 e gee < i 5 R R FES £|* : : Bae 2 oud 3 i at iy ey a 8 8 8 g : E ; e H 2 Hy : DED ESI 1G} q ie is SY e je Fa Pa Jz ra FD HLS 1B} je jz je uf jz g El i R E EB 3 iS " ie Ie iq 3 3 a) 2 | oO g r D £ PLB dey 2 ro s ; 3 : o y Je qe 8 ' : #7 i Hi, a pig N Pilg 2 4S 5 : eS § € 5 gyy 3 7 ay” e . 3 om (w-wyo) oyy “ddy (Bap) aseyd (Bap) ynwizy “Wed “Ua Period (sec) WesternGeco Rotation: 0.0° Sounding A034 WesternGeco Sounding A034 CJ Oo © © © E T= S268. Fiz T=7iasOFe T=aa5 ST Fe TaaiaTa re EE — x x x x g x 2 2 2 x és < T= e730re Es Es Ta 1450 Fe T= Saar T= Saere T= sear T= Baa re To ta7 re T=OsTaare B 3 2 2 g T=OsTeare ToOsTeare T=Oza0a Fz T=0Teao Fe T=0.064 Fz = : S ©) (#) () ® ~ T=06ea Fe T=0.0804 Fe T=00aTs Fe T=OOBTa re T=OnTaere BS 3 = £ 5 £ x < T=o00e4 Fe 7-005 Fe ercrd E G a < S £ & — = Zxy Impedance = Zxx Impedance ul uL a ml a a at 1 x Impedance Strike 10% 10° 10? tot 10° 10" 10? 10° Period (sec) WesternGeco Sounding A035 Rotation: 0.0° ounain A 9 Westemaeco Sounding A035 E T= BE Fe TBE RF T-BAR TROT TAS E * , £ % x x 2 2 2 x a a < T= eaTOFe Eo T= tana T= 45H T= eat re T= Saar T= aor T= a25 re T= Tat Re ToOaTaare ® 2 @ g T=OSiaar ToOasT Fz T=OzoTa Fe T=Oazea re T=OnaTO re = a x x x x * _ T=OOsaar T=ooae re T=OOaSE Fe T=oTeo re TODO Fe a © x x x 2 € 3 £ BI < 180. T=00065 Fiz T=oa0o Fe T=O0OEF @ Z rotation 2 10P TEI E ' 3 a < S £ & — Zxy Impedance ‘2x Impedance Impedance Strike WesternGeco Rotation: 0.0° Sounding A036 Sounding A036 WesternGeco (®) @) @) @) © — € T= a7 Fe THOT T=aa aT T=TESErE Tata are — s a s a “ a “ ° 2 x a a < T= o7aere T= aaze Fe To Saaa re T= a0a re Taare 72 SaeTe 7a 3aare 77 asta Ta aT Fe T=OSTG 8 2 oa 2 T=OSaeaFe TORS T TORT Fe T=OIGOEF: T=OETOFE = l QY & () =s Toner TODS TOBE FE TOOTaa Fa T=O OE Fz o oo 2 x x x £ 3 £ 5 < TODOS 7-000 T=ODOFE = Zrotation 0 Zetrike E S a < 5 £ a ae! = Zxy Impedance = Zxx Impedance x = Impedance Strike Period (sec) WesternGeco Seinaing ager Rotation: 0.0° ounding AO: . g WesternGeco Sounding A037 Ee TTF TeBRESEFE TEI T=TeSEFE TaTTSRTFE E x = » : 5 x 2 ° £ a a a <= T= 67.38 Hz T= 38.67 Hz T= 22.85 Hz T= 14.30 Hz T= 932Hz 7 Saar T= aaah T= aaah Taare T=OSTGEe SB s z= 2 8 7=0.5722 Hz 70.3871 He 7=0.2608 Hz 7=0.1648 Hz 7=0.1053 Hz = & : % s % % de } PhasexY b Phasevx — T=007aare T=00a6o Fz T=0.0s00F2 Toor T=OoT06 Fe T=O.0065 Re T=O00a0 Fe T=00026 Fez T=O.00T6 Fe —— = Zxy Impedance = Zxx Impedance x = Impedance Strike WesternGeco Rotation: 0.0° T= 30762 re T= Bat7 Fe T= a5 Ve T0150 Fe 7=0.0320 Fe Sounding A038 T= 55371 He T= 3750 Re T=0.a028 Fa T=0.0540 Fz T= 3762. Fe T= Sa 7a Fe T= So5re Ie OOO T=0STaa re T=00824 Fe T=0.0081 Fe T=0.0051 Fz 7=0.0080 Fz T= 6480. Fe T= 0434 re T= oaahe 708780 re T=0.1282 Fe T=00125 re WesternGeco T= 8268. Fe T= 160.82 re T= S50 re T= 147 He T=02014 Fe T=0.0206 Fe T=00020 He = Zxy Impedance = Zxx Impedance Sounding A038 Titow f tovx 8 Z strike © Z rotation e 8 (w-wyo) oyy ‘ddy 2 (Bap) aseyd (Bap) ynwizy sue ‘uaWIg © Zellip. 3 Z skew = Impedance Strike 107 10° 10! 10? Period (sec) 10? WesternGeco ar EP EPS OE ; ; (OJOMO | iL} 1): Cc 5 s By ie re je JONOIOHGNRI = i ™ aa ie a le Lt R E B Yk |e fe OOOH ANH SR! 2 = i = ie id ; @OHOVOHP | Oat es: i : 7 g|* i ie ie y x a OFOIOH GUSTS] g = Zxy Impedance = Zxx Impedance QD oO oO < aD s U ¢ = 52 ao 4 1 1 sg sy i i he E N as te ° IN 2 \ He 3 FA if : 3 BL s a NE g le 7 i (w-wyo) oyy “ddy (Bap) aseyd (Sap) ynwizy “ued "UaWuig = Impedance Strike qe qe qe 123 Z _3 7° 5 a 7 ws 10° 104 WesternGeco T= 8672 Re T= 7.30 He T0741 He T=0.0641 Fe T=0.0063 Fe Sounding A040 = T8000 Re T1196 Fe T= tare T=0.1076 Fe T=O.0T06 Fz 205.08 re T= 1864 re T= 1.90 re Ta0.1648 Fe T=o0T6o rz T= 288rz Ta027a7 Fe T0065 He 7=0.0026 Fe WesternGeco T= Sa 7are T= 487 re T= S5a.71 re T= 30762 he T= 550 Fe Ta0aaa0 Fe TaO0aTe re T=0.00a0 He Zxy Impedance = Zxx Impedance = Impedance Strike 2° t OT tome eemeec nee teed ee tooeens < SD £ oD < 2 3 an 1 : x : 5 i 5 = bo a 8 i ; : be 5 er 8 5 i 8 k- Ss « a N Et 3 le te = & = 2 a . (w-wyo) oyy “ddy (Bap) eseug (Bap) yjnwizy “Wwe “UsWIG © Zellip. 8 Z skew 10! 10? 108 10° Period (sec) WesternGeco Rotation: 0.0° Sounding A041 3 F El =N El CoN E E Oo] * B| a iS 8 is < ‘ fi R q i 7 4 £ TU 5 i i — ie i B S| a) 7 ig 5 ie 4 e S : 8 8 ©! & R f fe je aa ef le 2 1 Ey i S e i 5 f E H jz je zfs it jz y | B} 5 g s HOO r : i Fa i iy ¥ (— 3]. 5 ig} x 8 5 ig 2 | ie al is IS g es q is Ie Ig § 3 Ss 7=00020 2 = Zxy Impedance = Zxx Impedance = Impedance Strike FRhoxy ¢ RrovK — FPnasexy $ Phaseyx — @ Zstrike '® Z rotation Ju % (w-wyo) oyy ‘ddy L L 3 8 (Bap) aseud (Bap) ynwizy o “ued “UaWIg 103 10? 10° 10° 10? 10° Period (sec) 10 e e 2 83s 3s 9 ; ; ; : ; tie |g : : : : : i que | gz 3 i i fe 838 3 ie Hy = S fe ig 338 < 4 4 i fe ie ees <y, : q 4 Is e ie ees 2 x a x x pee 2 A} « 7 « a: 3 Te 3 To | 5 5 | 2 2 jz je z F4 je fd Fa 2 je 8 : s E ; : 3 i : F ; dl E | GIONS IS} BiB HB HOES IG} | y ( | | ~ x i | je jz = é le 2 Fa E = Ea le | | R S Se IS IS e fe ° e F E | ; He i & i i . Sy. : By ie B | je Fa 2 é = * je Fa 2 2 2 Jz — (OCPOFOHTRIAN KI @B HSS BSL! re | * Ie je Ie ie ie ie le je e ie Ie ~ x x * x s x x x | je Fa je i : ie je * E é é é 8 g e = s ie 8 ‘ : is iS 3 i g 3, i je IOUOHOT OI |e} 1S BH FB LQie 8 x A x » 3 x x « = = | oO q o $ | qe a Ege te | a = p qe °° nond | *) Cc 3 | 9 =, no ‘ qe ---4 3 3 | é 4 é | , | | x ° 1 oe a N aI]% wee? N le. Lo a nqQe 8. = ® | 33 : 5 : 88 i § | 53 i PL He [ss bie 4 : |gs a N Ft N gs c N |Se i = "—E ° se . | 4% 8 : (w-wyo) oyy ‘ddy (Bap) aseyg (Bap) ynwizy “Wed “UdWIG (w-wyo) oyy “ddy (Bap) aseyd (Bap) ynwizy “Weg “UaWIg WesternGeco Rotation: 0.0° Sounding A044 WesternGeco = Zxy Impedance eg Fe = je je jE SILO |S |S Oe} rs is q q i is 2 Fa = Fe jE |e LS FL@ |LQONL] . Le 5 ke fi ie je 2 jE je jE jE SLB FOILS |-O FO} jE je je je je jE fg E E E FE E § 1S FO ]Sf-S|_@} : : : : : : SFB OFS |S O} T=00026 Fe Sounding A044 FP Anoxy § Rhovx — } Prasexy > PhaseYX — @ Z strike = Zrrotation % bey (w-wyo) oyy “ddy (Bap) aseud (6p) ynwizy “ue “UawIg 2xx Impedance = Impedance Strike 10° 10! 107 108 107 Period (sec) 10" 104 WesternGeco Rotation: 0.0° is e T= 487 Fe T=0aS66 Fe T=ooaTa Fe T=O10080 Fiz = Zxy Impedance = Zxx Impedance Impedance Strike Sounding A045 T=aie.14 re Baare BOSSI He T= 7553 Fe as T=0.0838 Fe T=o010a re T= T=0.6a17 He 7=0.06a1 Fz m T=010068 Hz T=71a50 He a\elfa lle WesternGeco Titre T= T=03067 Fe T=0026a re T=00026F2 T= 67aere == 7 e Bea T= Taare Sc = Te7T re T=OnT6a He 10° Sounding A045 10? to" 10! 10° Period (sec) 10? @ Z strike 10° Tito f Bhove ‘© Z rotation 10 i 8 (Bap) ynwizy “Wu "UdWIG (w-wyo) oyy “ddy (Sap) aseyd T=0.0063 Fz Ta 1450 He T= TAT Fe T=0.0870Rz T=0.1306 Fe T=0.0103 Fe T= 20332 Fe T= 607.03 = Zxy Impedance = Zxx Impedance = Impedance Strike = Impedance Strike T=OOTeO Fe = Zxy Impedance = Zxx Impedance Sounding A047 T= 2240 Fe Zaare = 7= 350.58 He Sounding A046 TaTaSaT Fe : TOR T= 250.78 He T1641 Fe T= 156 r T=0.0a46 re T=Ooata re T=0,00%0 Fe & © & % a C797 He T= 505hz T= eS gY & ey aod DIL Vv = T=00080 Fz 3268. Fz Batre T1719 Fz T= 3026 re T= sare T= T= & g &S QBI]O©O WesternGeco T= 8268. Fe WesternGeco T=00804 Fe T=o0T0s Fe © S + (3 4 & % @ potbtbe 7 2 {2 2 2 2 7 2 7 3 3 5 B ~ | ® . eget eo qe qe o~ 5 Ff 4e 8 3 = B }; 8 8 = 4 . 2 7 2) | J ' ay | x é x i 5 go | : mye fg pop 2 : nye é 7 | 8s Lo. ° 3 8 bo . - ° ge . = 2 + [38 i | bye [83 i i i ife | 8s = 1 3 gs « ie N N |3e@ p= i 7 Se i i na ® | e 2 %® 2 : 2 & © & & ® | | | (w-wyo) oyy ‘ddy (Gap) aseyd (Bap) ynwizy “Wued “UsWIG (w-wyo) oyy ‘ddy (Bap) aseud (Bap) ynwizy “uued “UdWIG WesternGeco i . T= S382 T-OS722 re 7=0.0664 Fe T=0,0066 Fz Sounding A048 Ta Tat oer T= s30Fz T=O8780 Fz 7=0,1000 Fe T=O0Tes re TOT Fe TOOTH SSSST He = Bieta re r T= 1450 Fe : : To Vat He T=0.2600 Fe Taare eo T= 2280 Fe T= aos He Ties0re WesternGeco T= T= 7. T=03784 Fe T=00a1a Fe Be] (35]| 23 7=0,0026 Fe T=00076 re 7=0,00%0 2 = Zxy Impedance = Zxx Impedance co t o < aD £ UD & Sa °° n ! ' x g 5 i 3 é S : 8 i > 5 3 z x 5 3 2 2 2 & 2 é é S 2 be bo . J * (w-wyo) oyy ‘ddy (Bap) aseyg (Bap) ynwizy “Wed “Ua © Zell. a Z skew = Impedance Strike 10° 10! 10? 10° Period (sec) 10°3 10? 10 104 WesternGeco Rotation: 0.0° Sounding A049 WesternGeco T=0.0031 Fe ololololal GIOVE Ole Qa Oot el. QO OlE eI]. 7=0.0051 Fz = Zxy Impedance Sounding A049 Titoxy Rove — F PhasexY ¢ PhaseYX — © Z strike © Zrrotation * (w-wyo) oyy ‘ddy (Bap) eseyg (Gap) ynwizy “We “USWIG 2 gt £5 33 g2 5 E ff NE we Ie 7 Ss qe qe ye $ Jo $40 nq? ° ah gi N a Period (sec) Sounding A050 T=o00T6 re T=00026 He WesternGeco Ed = é F E is 5 e 8 E 3 Y S f i ; F |" 1BNG! i 2 E i E 3 A e B E iz lz é R f i [eLelle@ [elele i lz e a | IS | | Ab T=0.0063 Fz = Zxy Impedance = Zxx Impedance (w-wyo) oyy “ddy (Bap) aseyg (6ep) ynwizy wo o = Da £ Uv & ian 5 on I | E | g! oeehebe bess 4 # x i 3 I 5 5 % Q ‘ : 82 i i ge ii | Sie EVITA RT aT qe : : it A 5 ' |$e i i i 2 ® “Wed “UdWIG © Zellip. ‘8 Z skew ui = Impedance Strike 102 10! 10° 10! 1 10 Period (sec) 10° 10 WesternGeco Rotation: 0.0° Sounding A051 WesternGeco @ (SII Slal SBI@lOlsl@ilel @ SIO ESI@ Na BI SIS Sole) GISISIST allel Zxy Impedance Sounding A051 ' e 2 = i = — 8 Zstrike © Z rotation (w-wyo) oyy *ddy (Bap) aseyd (6ap) ynuizy “wed “UawIg Zxx Impedance = Impedance Strike © Zell BZ skew at ww? 10? ot 0 Period (sec) ut ra 104 WesternGeco Sounding A052 T=0.0026 Fe T=0000 Hz WesternGeco SlOfOlsailal SlOTOlellal [OOPS 2I. OVOVOFONO], O l OTOLO Nell T=00086 Fz Zxy Impedance = Zxx Impedance Sounding A052 1 x ¥ 2 x to- > & £ = fe 3 Zstrke ‘© Z rotation (w-wyo) oyy “ddy (Bap) eseud (Bap) ynwizy “wued “UaWig © Zellip. 8 Zskew = Impedance Strike 10 10° 101 12 Period (sec) 10? ut 10° 104 WesternGeco T= aaah T0aTaare T=0.0884 Fe T=O0106 Fz Sounding A053 T=Teaaa Te T= Tat he OHO |MO}]@||}O D||DI1P]|D]|Y DB @||@/1@ BSB T=0.1504 Fz T=00T6o re T=0.00T6 Fz T= 55571 Fe T= S07 Bare T= 1641 Fe T= 61 re T=Oa02a Fi T=00aTa re T=O0080 He T= 4770. Fe Ta Sa7a He Saere T=0s7aare T= 7-006 Fe T=0.0083 He WesternGeco T= 8268, T= aaa Fe = Zxy Impedance oO wo o <x oD £ vv <4 a °o n ! i i E bs o 2 Le : 3 5 z j g é & & fe . (Gap) eseyg (Bap) ynwizy (w-wyo) oyy ‘ddy “Wed “UaWIG e 3t 25 383 2 3 ES £3 x3 RE 11 qe qe qe S qe Je qe S10 Blo fae ° By gqe N ° Period (sec) City of Akutan Akutan MT 2009 survey Operational Report APPENDIX G DIGITAL DATA ON CD All the project raw and processed data files are archived at Geosystem’s head office, Milan, on CD-ROM. The enclosed CD contains: MT DATA * EDI: SEG MT/EMAP Data Interchange Standard files, ASCII format. MT_Coordinates_Akutan.xls Files containing MT sounding coordinates (see section 1.2 for metric coordinate projection parameters). WinGLink Database WinGLink database (.wdb) with all MT data. Report Akutan-MT_OpsReport.pdf: Acrobat pdf file of this report. MT TIME SERIES MT Time Series are submitted separately on HD. GEOSYSTEM - WesternGeco EM G-1 October 2009