Jared R. Peacock
Kevin M. Denton
David A. Ponce
2019
Magnetotelluric data from Mountain Pass, CA, 2015, station mp357
ASCII data, shapefile, image
Denver, CO
U.S. Geological Survey
Additional information about Originator: Jared R. Peacock, https://orcid.org/0000-0002-0439-0224, Kevin M. Denton, https://orcid.org/0000-0001-9604-4021, David A. Ponce, https://orcid.org/0000-0003-4785-7354
https://doi.org/10.5066/P9JNPLPJ
Kevin M. Denton
David A. Ponce
Jared R. Peacock
David M. Miller
20190307
Geophysical characterization of a Proterozoic REE terrane at Mountain Pass, eastern Mojave Desert California
Publication
Geosphere
na
Denver, CO
U.S. Geological Survey
doi:xx.xxxx/xxxxxxxxx.x
This dataset consists of 65 magnetotelluric (MT) stations collected in 2015 near Mountain Pass, California. The U.S. Geological Survey acquired these data to create a regional conductivity model near the Mountain Pass mine. This work is in support of characterizing mineral deposits.
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:
mp357.edi
mp357.png
mp357.mth5
20170315
1630000000Z
20170316
1104390585Z
ground condition
As needed
-115.33547
-115.33547
35.53710
35.53710
None
Geology, Minerals, Energy, and Geophysics Science Center
GMEGSC
Mineral Resources Program
MRP
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:5c81b45de4b09388244766e2
Geographic Names Information System (GNIS)
Mojave
Ivanpah
Mountain Pass
Clark Mountain
San Bernardino County
Common Geographic Areas
California
Mescal Ranges
USGS Thesaurus
Proterozoic
Paleozoic
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
Mineral 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.
20170315
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).
20161010
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.
20161010
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/5b4008bfe4b060350a10c69e?name=Guide_to_Magnetotelluric_Data_Types.pdf.
MT_Dictionary.csv
A data dictionary describing attributes is accessible at, https://www.sciencebase.gov/catalog/item/5b4008bfe4b060350a10c69e?name=MT_DataDictionary.csv.
U.S. Geological Survey - ScienceBase
mailing and physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
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.
20200821
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