Robert C Witter

Radiocarbon ages, age-model code, and other supplemental data for Nelson et al. (2021), A maximum rupture model for the central and southern Cascadia subduction zone—assessing ages for coastal evidence of megathrust earthquakes and tsunamis

This data release contains supplemental data for the following paper: Nelson, A.R., DuRoss, C.B., Mahan, S.A., Gray, H.J., Engelhart, S.E., Witter, R.C., Hawkes, A.D., Horton, B.P., Kelsey, H.M., and Padgett, J.S., 2021, A maximum rupture model for the central and southern Cascadia subduction zone—assessing ages for coastal evidence of megathrust earthquakes and tsunamis: Quaternary Science Reviews 261, https://doi.org/10.1016/j.quascirev.2021.106922. The data include a compilation of new and previously published radiocarbon ages from the original cores from Bradley Lake of Kelsey et al. (2005; odt format), and tables of new and previously published radiocarbon data for 7 of the 13 tidal wetland sites along the...

Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Cascadia Megathrust, Cascadia subduction zone, Earthquake Hazard Program, GHSC, Geologic Hazards Science Center, All tags... Tsunami hazard planning, USGS Science Data Catalog (SDC), USGS:5908a1b3e4b0fc4e448ffe23, coastal hazards, earthquake contact, earthquake hazards, earthquake history, lake tsunami history, large earthquake ruptures, paleoearthquake correlation, radiocarbon dating, seismic hazard, tsunami contact, Fewer tags

Quaternary deposits of the 9-county San Francisco Bay Region: an areally continuous digital map database prepared from Knudsen and others (2000) and Witter and others (2006)

This digital map database provides an areally continuous representation of the Quaternary surficial deposits of the San Francisco Bay region merged from the database files from Knudsen and others (2000) and Witter and others (2006). The more detailed mapping by Witter and others (2006) of the inner part of the region (compiled at a scale of 1:24,000), is given precedence over the less detailed mapping by Knudsen and others (2000) of the outer part of the area (compiled at a scale of 1:100,000). The Quaternary map database is accompanied by a list of the map-unit names represented by polygon identities, a digital map index of the 1:24,000-scale topographic quadrangles of the region, and a figure illustrating the...

Tags: 1800s shoreline, Geomorphology, Quaternary, San Francisco Bay Region, San Francisco Bay Region, All tags... San Francisco Bay mud, Sedimentology, Seismology, Stratigraphy, USGS Science Data Catalog (SDC), biota, surficial deposits, Fewer tags

Field reconnaissance of ground failure triggered by shaking during the 2018 M7.1 Anchorage, Alaska, earthquake

These data present geolocated photographs, GPS tracks, and field-mapped ground failures collected during the USGS reconnaissance of ground failures following the 2018 M7.1 Anchorage Earthquake.

Tags: Alaska, Anchorage, Geomorphology, Landslides, Liquefaction, All tags... Seismology, USGS Science Data Catalog (SDC), Fewer tags

This data release contains data sets associated with the 2023 50-State National Seismic Hazard Model Update. The 2023 50-State National Seimsic Hazard Model (NSHM) Update includes an update to the NSHMs for the conterminous U.S (CONUS, last updated in 2018), Alaska (AK, last updated in 2007), and Hawaii (last updated in 2001). Data sets include inputs like seismicity catalogs used as input to the smoothed seismicity model and updated induced seismicity zone polygons in the central and eastern U.S., as well as outputs like hazard curves and uniform-hazard ground motion values. Plots of selected data sets are also included. The data sets provided here are primarily for the 2023 CONUS NHSM and 2023 AK NSHM. Additional...

Categories: Data; Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Alaska, Conterminous United States, Earthquake, Hawaii, Hazard, All tags... Map Service, National Seismic Hazard Model, OGC WFS Layer, OGC WMS Layer, OGC WMS Service, Seismic, Seismology, USGS Science Data Catalog (SDC), earthquake hazard, geophysics, seismology, Fewer tags

Compiled onshore and offshore paleoseismic data along the Cascadia Subduction zone

The USGS Powell Center Cascadia earthquake hazards working group compiled published onshore and offshore paleoseismic data along the Cascadia subduction zone, spanning sites from Vancouver Island to the Mendocino triple junction. Evidence for megathrust rupture includes coastal land-level change, tsunami inundation, onshore shaking proxies such as landslides or liquefaction, and offshore shaking proxies such as marine turbidites. The quality of paleoseismic data for megathrust rupture along the Cascadia subduction zone collected over the past three decades varies because analytical capabilities and data collection methodologies have evolved. Thus, as part of the compilation, we also present a ranking scheme to assess...

Categories: Data; Tags: Aquatic Biology, British Columbia, California State, Cascadia subduction zone, Ecology, All tags... Geomorphology, Marine Geology, Oregon State, Sedimentology, Seismology, Stratigraphy, USGS Science Data Catalog (SDC), Washington State, earthquake, economy, lacustrine turbidite, landslide, liquefaction, marine turbidite, paleoseismic, subsidence, tsunami, Fewer tags