Katie M. Hulsey Burke J. Minsley Jade W. Crosbie Ryan F. Adams Carole D. Johnson Eric A. White Emilia L. Bristow Amy M. Gahala 20250923 tabular digital data https://doi.org/10.5066/P13WHWZR In November 2022, Ground-based time domain electromagnetic (TEM) data and Horizontal-to-Vertical Spectral Ratio (HVSR) passive seismic soundings were acquired by the U.S. Geological Survey (USGS) at 27 locations throughout the Illinois River Basin (IRB). The USGS collected these data to characterize the subsurface resistivity structure and depth to bedrock in support of the USGS Next Generation Water Observing System (NGWOS) IRB program and for comparison to Airborne Electromagnetic and magnetic survey data. This data release includes the raw and processed TEM data and inverted soundings showing resistivity (in ohm-m) with depth. HVSR raw data is included in binary files (Tromino), miniseed (SmartSolo), and ascii files (both instruments). HVSR processed data is included in .jpg files with plots of single component spectra and horizontal to vertical spectral ratio. Data were collected to characterize the subsurface resistivity structure and depth to bedrock in support of the USGS Next Generation Water Observing System (NGWOS): Illinois River Basin program and for comparison to Airborne electromagnetic and magnetic survey data. "NGWOS_IRB_TEM_HVSR_SiteList.csv" file contains list of all sites where TEM and/or HVSR data was collected. "NGWOS_IRB_TEM_HVSR_Sites.shp" GIS shapefile contains all sites where TEM and/or HVSR data was collected. DEM in the “Point_DEM_Elev” column is the elevation value in meters (North American Vertical Datum 1988). This value is from a Digital Elevation Model (DEM) for the interpretation of NGWOS IRB geophysical data at a regional scale appropriate for the NGWOS IRB Airborne Electromagnetic survey data. The DEM is re-sampled at resolution of 500 meter cell size from the higher-resolution 10 meter cell size of the Illinois StreamStats DEM (Shafer and Sharpe, 2023), which can be accessed at https://doi.org/10.5066/P9YIAUZQ. 20221031 20221104 ground condition Complete None planned -91.0000 -87.50000 42.50000 39.0000 ISO 19115 Topic Category biota None Geophysics Aquifer characterization Time domain electromagnetic TEM NGWOS HVSR Horizontal-to-vertical spectral ratio Passive seismic Tromino SmartSolo USGS Metadata Identifier USGS:666323b7d34e4d5e848413e7 None Illinois Illinois River Basin None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Katie (KT) M. Hulsey U.S. Geological Survey, Central Midwest Water Science Center Hydrologist mailing

401 NW Capital Drive

Lees Summit MO 64086 US 816-554-3489 217-328-9770 khulsey@usgs.gov Acknowledgements Support and field assistance: Illinois State Water Survey and Illinois State Geological Survey Land access for data collection: Illinois Department of Natural Resources, U.S. Department of Agriculture Natural Resources Conservation Service, U.S. Fish and Wildlife Service, Bourbonnais Township Park District, Champaign County Forest Preserve District, Macon County Conservation Area, Wetland Initiative Data includes raw instrument files, with these data being processed to varied degrees, depending on the specific objectives of the work. Data were reviewed for consistency. 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. Descriptions of data acquisition and processing are included in the metadata for the individual techniques on child item pages. 2022 Albers Conical Equal Area 29.5 45.5 -96.0 23.0 0.0 0.0 coordinate pair 0.001 0.001 meters North American Datum of 1983 (NAD 83) Geodetic Reference System 1980 6378137.000000 298.257222 North American Vertical Datum of 1988 0.01 meters Attribute values NGWOS_IRB_TEM_HVSR_SiteList.csv Comma Separated Values (CSV) file containing data. Producer Defined Site_number Number (string) identifying geophysical survey sites. Producer Defined 1 34 Site_name Text string with name of geophysical survey site Producer Defined Text strings with site names Instrument_SerialNumber Text string with name geophysical instrument followed by serial number. Producer Defined WalkTEM_615070036 TEM geophysical instrument and serial number. Producer defined Tromino_486 Passive seismic geophysical recording instrument and serial number. Producer defined SmartSolo IGU-16HR_453020959 Passive seismic geophysical recording instrument and serial number. Producer defined WalkTEM2_620110032 TEM geophysical instrument and serial number. Producer defined Tomino_618 Passive seismic geophysical recording instrument and serial number. Producer defined Tomino_485 Passive seismic geophysical recording instrument and serial number. Producer defined Date_Collected Date on which the measurement was collected Producer Defined 10/31/2022 11/04/2022 PointID Number assigned to each measurement point. In some cases more than one measurement point exists within a given site. Producer Defined 1 73 Point_Lon_WGS84dd Point longitude in World Geodetic System 1984 decimal degrees. "Missing" means no longitude was recorded at the point. Producer Defined -90.926388 -87.882659 decimal degrees Point_Lat_WGS84dd Point latitude in World Geodetic System 1984 decimal degrees. "Missing" means no latitude recorded at point. Producer Defined 38.940063 42.476357 decimal degrees Point_WGS84_elevation_meters Point elevation in meters above mean sea level in World Geodetic System 1984. "Missing" means no elevation was recorded at that point. Producer Defined 98.297 240.436 meters Point_X_Albers5070 Point easting in Conus Albers NAD83 Producer Defined 429765.1064 675135.8761 meters Point_Y_Albers5070 Point easting in Conus Albers NAD83 Producer Defined 1781658.262 2190541.08 meters Point_DEM_Elev Elevation value in meters (North American Vertical Datum 1988). Value sampled from digital elevation model (DEM). See Supplemental Information for additional detail. Producer Defined 128.385 272.055 meters NGWOS_IRB_TEM_HVSR_Sites.shp (compressed as "NGWOS_IRB_TEM_HVSR_Sites.zip" Shapefile containing site data. Producer Defined FID Feature ID. Producer Defined 0 88 Shape Shape (representation in shapefile) Producer Defined Point Feature is represented in shapefile as a point Producer defined Site_numbe (alias Site_number) Number (string) identifying geophysical survey sites. This is the same as Site_number in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined 1 34 Site_name Text string with name of geophysical survey site Producer Defined Text strings with site names Instrument Text string identifying the geophysical instrument used for this point. Producer Defined WalkTEM2-HGB TEM geophysical instrument Producer defined Tromino_486 passive seismic geophysical recording instrument Producer defined SmartSolo passive seismic geophysical recording instrument Producer defined WalkTEM-GGG TEM geophysical instrument Producer defined Tomino_618 passive seismic geophysical recording instrument Producer defined Tomino_485 passive seismic geophysical recording instrument Producer defined Date_Colle (alias Date_Collected) Date on which the measurement was collected. This is the same as Date_Collected in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined 10/31/2022 11/04/2022 PointID Number assigned to each measurement point. In some cases more than one measurement point exists within a given site. Producer Defined 1 73 Point_Lon_ (alias Point_Lon_WGS84dd) Point longitude in World Geodetic System 1984 decimal degrees. "Missing" means no longitude was recorded at that point. This is the same data as Point_Lon_WGS84dd in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined -90.926388 -87.882659 decimal degrees Point_Lat_ (alias Point_Lat_WGS84dd) Point latitude in World Geodetic System 1984 decimal degrees. "Missing" means no latitude was recorded at that point. This is the same data as Point_Lat_WGS84dd in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined 38.940063 42.476357 decimal degrees Point_WGS8 (alias Point_WGS8_elevation_meters) Point elevation in meters above mean sea level in World Geodetic System 1984. "Missing" means no elevation was recorded at that point. This is the same data as Point_WGS8_elevation_meters in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined 98.297 240.436 meters Point_X_Al (alias Point_X_Albers5070) Point easting in Conus Albers NAD83. This is the same data as Point_X_Albers5070 in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined 429765.1064 675135.8761 meters Point_Y_Al (Point_Y_Albers5070) Point easting in Conus Albers NAD83. This is the same data as Point_Y_Albers5070 in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined 1781658.262 2190541.08 meters Point_DEM_ (Point_DEM_Elev) Elevation value in meters (North American Vertical Datum 1988). Value sampled from digital elevation model (DEM). See Supplemental Information for additional detail. This is the same data as Point_DEM_Elev in 'NGWOS_IRB_TEM_HVSR_SiteList.csv'. Producer Defined 128.385 272.055 meters GS ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 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. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Digital Data https://doi.org/10.5066/P13WHWZR None 20250923 Emilia L Bristow U.S. Geological Survey, Central Midwest Water Science Center Hydrologist mailing and physical

400 S Clinton St, Federal Building

Iowa City IA 52240 US 319-358-3609 ebristow@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998