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This dataset supercedes an earlier data release and includes all previous data in addition to data from 2019. These data represent the network-adjusted results of relative- and absolute-gravity surveys. Relative-gravity surveys were carried out using a Micro-g LaCoste D-series relative-gravity meter. The effect of solid Earth tides and ocean loading were removed from the data. Instrument drift was removed by evaluating gravity change during repeated measurements at one or more base stations. Absolute-gravity surveys were carried out using a Micro-g LaCoste, Inc. A-10 absolute-gravity meter. Vertical gradients between the different measuring heights of the absolute- and relative-gravity meters were measured using...
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This data release provides a map of the time-averaged shear-wave velocity in the upper 30 m (Vs30) for California using the method described by Thompson and others (2014). There are two adjustments to the algorithm described by Thompson and others (2014), which is built on the geology-based Vs30 map by Wills and Clahan (2006). In this data release, we use the Wills and others (2015) updated geology-based Vs30 map. The second change is that we have adjusted the kriging procedure so that measured Vs30 values do not affect the predictions across distinctly different geologic units. July 2022 Update (ver. 2.0) Resolution is now 3 arcseconds instead of 7.5 arcseconds Fixed a code error that prevented some of the Vs30...
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Airborne electromagnetic (AEM), magnetic, and radiometric data were acquired in late February to early March 2018 along 2,364 line-kilometers in the Shellmound, Mississippi study area. Data were acquired by CGG Canada Services, Ltd. with three different helicopter-borne sensors: the CGG Canada Services, Ltd. RESOLVE frequency-domain AEM instrument that is used to map subsurface geologic structure at depths up to 100 meters, depending on the subsurface resistivity; a Scintrex CS-3 cesium vapor magnetometer that detects changes in deep (hundreds of meters to kilometers) geologic structure based on variations in the magnetic properties of different formations; and a Radiation Solutions RS-500 spectrometer that detects...


    map background search result map search result map An Updated Vs30 Map for California with Geologic and Topographic Constraints (ver. 2.0, July 2022) Airborne electromagnetic, magnetic, and radiometric survey, Shellmound, Mississippi, March 2018 (ver. 2.0, March 2024) Repeat microgravity data from Tucson Basin and Avra Valley, Arizona, 2016-2019 Airborne electromagnetic, magnetic, and radiometric survey, Shellmound, Mississippi, March 2018 (ver. 2.0, March 2024) Repeat microgravity data from Tucson Basin and Avra Valley, Arizona, 2016-2019 An Updated Vs30 Map for California with Geologic and Topographic Constraints (ver. 2.0, July 2022)