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In October and November 2016-2017, transient electromagnetic (TEM) data, also called time domain electromagnetic (TDEM) surveys, were acquired at 120 locations in the Genesee Valley, Livingston County, New York, in order to characterize the subsurface resistivity structure in support of a U.S. Geological Survey groundwater investigation. The TEM data were collected as part of a project to evaluate geophysical methods to characterize the valley-fill sediments, underlying bedrock, and salinity of the subsurface. TEM data were collected using an ABEM WalkTEM unit (acquisition software V 1.1.0 and newer) using two transmitter loop (Tx) sizes, 100 by 100 meter square and 40 by 40 meters square, a center-loop receiver...
Categories: Data;
Tags: Aquifer Mapping,
Electromagnetic surveying,
Genesee River Valley,
Geophysics,
Geophysics,
This data release contains two related datasets acquired for the uncrewed aerial system aeromagnetic test survey at the Boulder Magnetic Observatory. The first contains the raw magnetic data for the set of four test flights, and the second contains the compensated magnetic data for the same four flights. Details of the data are recorded in the metadata files associated with each dataset.
Note: this data release has been depecrated. Find the updated version here: https://doi.org/10.5066/P9X8RUBW. Electromagnetic (EM) geophysical methods provide information about the bulk electrical conductivity of the subsurface. EM data has been widely used to investigate aquifers and geologic structures. In the following study, the United States Geological Survey conducted a boat-towed, waterborne transient electromagnetic (FloaTEM) survey to examine conductivity within the subsurface of the Delaware River channel. These conductive zones determine the location of the groundwater freshwater/saltwater interface within the Delaware River, downstream from Wilmington, DE. The FloaTEM system transmits a primary electrical...
Surface-based 2D electrical resistivity tomography (ERT) surveys were used to investigate the distribution of permafrost at wetland sites on the alluvial plain north of the Tanana River, 20 km southwest of Fairbanks, Alaska, in June and September 2014. The sites contained habitat types characteristic of interior Alaska, including thermokarst bog, forested permafrost plateau, and a rich fen. These habitats range from treed to open and vary in groundcover vegetation and peat thickness. Individual surveys used a cable with 56 electrodes at 2-m spacing. At a fen site, ERT surveys were performed across a mixed spruce forest area across a vegetation gradient into an open fen area. At a bog site,surveys were performed...
A suite of geophysical methods was used along the Des Moines River, Beaver Creek, and in the Des Moines River floodplain in Des Moines, Iowa to support the hydrogeologic characterization of the alluvial aquifer associated with the river. The aquifer consists of sands and gravels underlain by weathered shale bedrock. Groundwater from the aquifer along with surface water sources are used for municipal drinking water for the City of Des Moines and surrounding communities. The raw data provided in this data release are minimally processed to filter out erroneous measurements. Data provided in this data release includes continuous resistivity profiling (CRP) and continuous seismic profiling (CSP) that were collected...
Marine geophysical mapping of the Queen Charlotte Fault in the eastern Gulf of Alaska was conducted in 2016 as part of a collaborative effort between the U.S. Geological Survey and the Alaska Department of Fish and Game to understand the morphology and subsurface geology of the entire Queen Charlotte system. The Queen Charlotte fault is the offshore portion of the Queen Charlotte-Fairweather Fault: a major structural feature that extends more than 1,200 kilometers from the Fairweather Range of southern Alaska to northern Vancouver Island, Canada. The data published in this data release were collected along the Queen Charlotte Fault between Cross Sound and Noyes Canyon, offshore southeastern Alaska from May 18 to...
Geophysical and Other Data From an Irrigation Monitoring Experiment at Haddam Meadows, CT, July 2019
An irrigation monitoring experiment was performed in Haddam Meadows State Park, Connecticut, on July 16, 2019. Prior to this experiment, ground penetrating radar (GPR), frequency domain electromagnetics (FDEM), and electrical resistivity tomography (ERT) geophysical data were collected over a 20 meter by 10-meter grid to provide baseline information. A vertical soil moisture probe was installed in the center of this area that recorded volumetric water content, temperature, and electrical conductivity at 9 discrete depths down to 1 meter below land surface. Over the next 8 hours, 5,300 liters of irrigation water (with specific conductance of 1,000 microSiemens per centimeter) was sprayed as evenly as practical over...
A model of the lower seismogenic depth distribution of earthquakes in the western United States was developed to support models for seismic hazard assessment that will be included in the 2023 USGS National Seismic Hazard Model. This data release presents a recalibration using the hypocentral depths of events M>1 from the Advanced National Seismic System Comprehensive Earthquake Catalog from 1980 to 2021. For higher precision and better resolution in the model, the data were supplemented with seismicity from southern California that was relocated by Hauksson and others (2012). Along the San Andreas Fault, the deepest seismogenic depths are located at 23 km around the Cholame segment, whereas the shallowest depths...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Geophysics,
Seismology,
USGS Science Data Catalog (SDC),
United States,
earthquake occurrences,
Seismicity catalogs, GIS shapefiles, gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2014 National Seismic Hazard Model for the Conterminous U.S. Probabilistic seismic hazard data and maps of the conterminous U.S. for peak ground acceleration (PGA) and 0.2 and 1.0 second spectral acceleration at probability levels of 2 percent in 50 years (annual probability of 0.000404) and 10 percent in 50 years (annual probability of 0.0021), assuming firm rock soil conditions at 760 m/s, are available. Hazard was calculated on a 0.05 degree by 0.05 degree grid, defined by a bounding box encompassing the conterminous U.S. (-125 to -65 degrees longitude...
Seismicity catalogs, gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2002 National Seismic Hazard Model for the Conterminous U.S. Seismicity catalogs are available for the western U.S. (in Mw) and central and eastern U.S. (in mb). Probabilistic seismic hazard data and maps of the conterminous U.S. for peak ground acceleration (PGA) and 0.1, 0.2, 0.3, 0.5, 1.0 and 2.0 second spectral acceleration at probability levels of 2 percent in 50 years (annual probability of 0.000404) and 10 percent in 50 years (annual probability of 0.0021), assuming firm rock soil conditions at 760 m/s, are available. Hazard was calculated on a 0.1 degree by 0.1...
Gridded ground motion data and mapped gridded ground motion values are available for the 1999 Alaska Seismic Hazard Model. Probabilistic seismic hazard data and maps of Alaska and the Aleutians for peak ground acceleration (PGA) and 0.2, 0.3, and 1.0 second spectral acceleration at probability levels of 2 percent in 50 years (annual probability of 0.000404) and 10 percent in 50 years (annual probably of 0.0021), assuming firm rock soil conditions at 760 m/s, are available. Development of the 1999 Alaska Seismic Hazard Model is documented in the USGS Open-File Report 99-36 (https://doi.org/10.3133/ofr9936). This dataset is considered a legacy dataset. The original dataset was released at the time of publication...
VS30, the time-averaged shear-wave velocity (VS) to a depth of 30 meters, is a key index adopted by the earthquake engineering community to account for seismic site conditions. VS30 is typically based on geophysical measurements of VS derived from invasive and noninvasive techniques at sites of interest. Owing to cost considerations, as well as logistical and environmental concerns, VS30 data are sparse or not readily available for most areas. Where data are available, VS30 values are often assembled in assorted formats that are accessible from disparate and (or) impermanent Websites. To help remedy this situation, we compiled VS30 measurements obtained by studies funded by the U.S. Geological Survey (USGS) and...
Categories: Data;
Tags: Geophysics,
Seismology,
USGS Science Data Catalog (SDC),
United States,
earthquake seismology,
We generated digital elevation models (DEMs) using pre- and post-event in-track stereo 0.5 m resolution panchromatic Worldview 1 and 2 images (©2019, DigitalGlobe) using the Surface Extraction from TIN-based Searchspace Minimization (SETSM) software [Noh and Howat, 2015] running on the University of Iowa Argon supercomputer (Table S1). The post-event DEMs exhibit along-track striping artifacts common to the Worldview 2 sensor. While de-striping tools, for example within NASAs Ames Stereo Pipeline [Shean et al., 2016], are commonly applied to resolve this issue, a de-striping correction has not been developed for this latitude. Noh, M.-J., and I. M. Howat (2015), Automated stereo-photogrammetric DEM generation...
In April 2017, the U.S. Geological Survey acquired high resolution P- and S-wave seismic data across the suspected trace of the West Napa Fault zone in St. Helena, California. We acquired seismic reflection, refraction, and guided-wave data along a 215-m-long profile across the expected trend of the West Napa Fault zone. To acquire the reflection and refraction data, we co-located shots and geophones, spaced every 2 m along the profile. We used 109 SercelTM L40A P-wave (40-Hz vertical-component) geophones with a sensitivity of 22.34 volts/meter/second to record 108 P-wave shots, and 109 SercelTM L28-LBH S-wave (4.5-Hz horizontal-component) geophones with a sensitivity of 31.3 volts/meter/second to record 108 S-wave...
Categories: Data;
Tags: Geophysics,
Saint Helena,
Seismology,
USGS Science Data Catalog (SDC),
earthquakes,
More than 11,500 well records, such as geophysical logs, drilling descriptions, and published hydrogeologic framework information, were evaluated to help characterize the framework of hydrogeologic units in and near Gaines, Terry, and Yoakum Counties, Texas. Additional geophysical data were collected to improve the spatial coverage across the study area and to reduce uncertainty with regard to hydrogeologic unit extents. The evaluation of existing data plus the collection of new geophysical data provided that basis for developoing a refined understanding of how the saturated thickness of the Ogallala and Edwards-Trinity aquifers vary throughout the study area.
The U.S. Geological Survey (USGS) has collected or incorporated over 20,000 physical property measurements into an ASCII database. These data are primarily from the western U.S. and Alaska and are dominated by granitic rock samples from the Sierra Nevada (compiled by Sikora and others, 1991), but also include a range of other commonly found rocks types. The data include density, magnetic susceptibility, and in some cases, remanent magnetic properties. Density data for more recently collected samples include grain, dry-bulk, and saturated-bulk density measurements. Sample locations are in the North American Datum of 1927 (NAD27) and elevations are in the National Geodetic Vertical Datum of 1929 (NGVD29). These physical...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Density,
Geophysical studies,
Geophysics,
Magnetic properties,
Physical Properties,
The collection of borehole geophysical logs data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the Cristex Drum National Priorities List Superfund Site near Oxford, North Carolina, during January through March 2016. In an effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants, borehole geophysical log and image data collection, which included the delineation of more than 150 subsurface features (primarily fracture orientations) in 3 open borehole wells.
Time series electromagnetic induction-log (TSEMIL) datasets are collected from polyvinyl chloride (PVC) cased or uncased monitoring wells to evaluate changes in water conductivity over time. TSEMIL datasets consist of a series of individual electromagnetic induction logs collected at a frequency of months or years that have been compiled into a dataset by eliminating small uniform offsets in bulk conductivity between logs likely caused by minor variations in calibration. At depths where water conductivity is not changing through time, each log is typically within about ±15 mS/m of the median of the dataset at any given depth, which is within the stated repeatability specifications of the probe (Mount Sopris Instrument...
Airborne electromagnetic (AEM) and magnetic survey data were collected during February 2016 along 300 line kilometers in the western Yukon Flats near Stevens Village, Alaska. Data were acquired with the CGG RESOLVE frequency-domain helicopter-borne electromagnetic systems together with a Scintrex Cesium Vapour CS-3 magnetometer. The AEM average depth of investigation is about 100 m. The survey was flown at a nominal flight height of 30 m above terrain along widely spaced reconnaissance lines. This data release includes raw and processed AEM data and laterally-constrained inverted resistivity depth sections along all flight lines. This release also includes unprocessed and processed magnetic data that has been drift...
This item contains a single text file containing the station information for each station in the dataset that contains a peak ground displacement observation about the GNSS noise floor. The text file is organized in the following format: EventYear, Event Magnitude (Mw), Station ID, Station Longitude, Station Latitude, Station Elevation, Station Hypocentral Distance, PGD (meters)
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