Jared R. Peacock 2019 ASCII data, shapefile, image Denver, CO U.S. Geological Survey Additional information about Originator: Jared R. Peacock, https://orcid.org/0000-0002-0439-0224 https://doi.org/10.5066/P99BB690 J. R. Peacock J. Glen B. Ritzinger T. Earney W. Schermerhorn D. Siler 20180404 Publication Geothermal Research Council Transactions 42 Denver, CO U.S. Geological Survey doi:xx.xxxx/xxxxxxxxx.x This dataset consists of 24 magnetotelluric (MT) stations collected in 2017 in Gabbs Valley, Nevada. The U.S. Geological Survey acquired these data as part of Phase 2 of the Nevada Play Fairway Analysis Project led by the University of Nevada at Reno and funded by the Department of Energy (grant number DE-EE0006731) with support from the U.S. Geological Survey's Energy Program. The purpose of this data release is to provide MT station locations, time-series data, and processed transfer functions to the public. This data product contains raw time-series data (*.mth5 files) and remote-referenced magnetotelluric (MT) transfer functions (TFs), which define the frequency dependent linear relations between components of electromagnetic (EM) field variations measured at a single site (*.edi files). Two types of TF are provided for most sites, impedance data relating horizontal electric and magnetic fields and tipper data, relating vertical and horizontal magnetic fields. All of the TFs provide input data for subsequent MT inversion and interpretation. They are estimated from the raw EM time series by (a) Fourier transforming data in a series of short overlapping time windows, and (b) applying robust regression methods to calculate TFs from the resulting spectral field estimates. For remote reference processing, data from one or more synchronously recording sites are used for more effective signal/noise separation. The supplied TFs are calculated for a range of periods (which may vary, depending on instrumentation and deployment time), as well as estimation error covariances. References relevant to this release include: Chave, A.D. and D. J. Thompson, 2004, Bounded influence estimation of magnetotelluric response functions, Geophysical Journal International, 157, pp. 988-1006. Documentation for robust MT data processing program BIRRP by Dr. Alan Chave http://www.whoi.edu/science/AOPE/people/achave/Site/Next1.html This metadata documents the full suite of MT data for this site and includes the files below. Their contents are described in the PDF Guide_to_MT_Data_Types.pdf and an accompanying data dictionary (see entities and attributes for more information). File List: gv12.edi gv12.png gv12.mth5 20171112 1515000000Z 20171113 0909419921Z ground condition Complete As needed -118.13670 -118.13670 38.79535 38.79535 None Geology, Minerals, Energy, and Geophysics Science Center GMEGSC Energy Resources Program ERP Magnetotellurics MT Time Series Impedance Apparent Resistivity Phase Tipper Earth Magnetic Field ISO 19115 Topic Categories GeoscientificInformation USGS Thesaurus geophysics electromagnetic surveying magnetotelluric surveying USGS Metadata Identifier USGS:5ca6cbaee4b0c3b0064c2cd7 Geographic Names Information System (GNIS) Gabbs Valley Mineral County Common Geographic Areas Nevada Gabbs Valley Range USGS Thesaurus Mesozoic Cenozoic None There is no guarantee concerning the accuracy of the data. Any user who modifies the data is obligated to describe the types of modifications they perform. Data have been checked to ensure the accuracy. If any errors are detected, please notify the originating office. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to https://www2.usgs.gov/laws/privacy.html for the USGS disclaimer Jared R. Peacock U.S. Geological Survey Mailing and physical

MS989 345 Middlefield Rd.

Menlo Park CA 94025 USA 650-329-4833 jpeacock@usgs.gov Energy Resources Program No formal attribute accuracy tests were conducted. No formal logical accuracy tests were conducted. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Spatial locations were determined from hand-held global positioning system (GPS) devices. In general, the GPS units used by field scientists recorded sample locations to within 100 feet (30 meters) of the true location. The locations were verified using a geographic information system (GIS) and digital topographic maps. Elevations were determined from USGS, The National Map, Bulk Point Query Service based on the USGS 3DEP (3D elevation program) 1/3 arc-second layer (10-meter). Vertical accuracy was not assessed for this specific dataset. The overall absolute vertical accuracy of the seamless DEMs within the conterminous United States (2013), expressed as the root mean square error (RMSE) of 25,310 reference points, was 1.55 meters (USGS, 2014 - http://dx.doi.org/10.3133/ofr20141008). The vertical accuracy varies across the U.S. as a result of differences in source DEM quality, terrain relief, land cover, and other factors. Time-series electric and magnetic field data were collected using wideband magnetotelluric instrumentation at each site location. These data are provided in HDf5 format (*.mth5 files) for all stations. 20171112 Fourier spectra were calculated for windowed time-series data (*.mth5 files) and used to calculate cross- and auto-power spectra. Impedance and tipper transfer functions (see *.edi files) were calculated at each station. System and sensor responses (in *.mth5 files) were deconvolved during this process. By this process, transfer function estimates were made for particular frequency bandwidths for each data run (4096 and 256 Hz sampling frequencies). 20171124 The transfer function estimates provided in the *.edi files and displayed in the *.png files were constructed by selecting optimal TF estimates at each period from a suite of data runs. High (4096 Hz sampling rate) and low (256 Hz sampling rate) frequency wideband recordings provided TF estimates for 1000-1 Hz and 0.001-1 Hz, respectively. Optimal TFs were selected based on examination of phase slope, smooth curve assumptions, and operator discretion. 20171124 0.0197305745 0.0273088247 Decimal seconds D_WGS_1984 WGS_1984 6378137.0 298.257223563 Guide_MT_Data.pdf The file, Guide_MT_Data.pdf, describes available magnetotelluric data types from the USGS. This report describes typical magnetotelluric instrumentation and the various data types required in MT processing and data quality assessment (including electric and magnetic field time-series, instrument response files, MT HDF5 format (MTH5), and transfer functions), accessible at, https://www.sciencebase.gov/catalog/item/5ca64a53e4b0c3b0064c26ac?name=Guide_to_Magnetotelluric_Data_Types.pdf. MT_Dictionary.csv A data dictionary describing attributes is accessible at, https://www.sciencebase.gov/catalog/item/5ca64a53e4b0c3b0064c26ac?name=MT_DataDictionary.csv. Science Base U.S. Geological Survey Mailing and physical

Building 810, Mail Stop 302, Denver Federal Center

Denver CO 80255 USA 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. 20200820 Jared R. Peacock U.S. Geological Survey Research Geophysicist Mailing and physical

MS989 345 Middlefield Rd.

Menlo Park CA 94025 USA 650-329-4833 jpeacock@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998