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Staff from Alaska Earthquake Center, Geophysical Institute and Alaska Division of Geological & Geophysical Surveys evaluated potential tsunami hazards for the city of Sand Point, on Popof Island in the Shumagin Islands archipelago. We numerically modeled the extent of inundation from tsunami waves generated by local and distant earthquake sources. We considered the results in light of historical observations. The worst-case scenarios are defined by analyzing results of the sensitivity study of the tsunami dynamics with respect to different slip distributions along the Aleutian megathrust. For the Sand Point area, the worst-case scenarios are thought to be thrust earthquakes in the Shumagin Islands region with magnitudes...
ShakeMap is a product of the USGS Earthquake Hazards Program in conjunction with the regional seismic networks. ShakeMaps provide near-real-time maps of ground motion and shaking intensity following significant earthquakes. These maps are used by federal, state, and local organizations, both public and private, for post-earthquake response and recovery, public and scientific information, as well as for preparedness exercises and disaster planning.
Types: Citation;
Tags: ANSS,
Advanced National Seismic System,
ComCat,
Comprehensive Earthquake Catalog,
Earth,
A scenario represents one realization of a potential future earthquake by assuming a particular magnitude, location, and fault-rupture geometry and estimating shaking using a variety of strategies. In planning and coordinating emergency response, utilities, local government, and other organizations are best served by conducting training exercises based on realistic earthquake situations—ones similar to those they are most likely to face. ShakeMap Scenario earthquakes can fill this role. They can also be used to examine exposure of structures, lifelines, utilities, and transportation corridors to specified potential earthquakes. A ShakeMap earthquake scenario is a predictive ShakeMap with an assumed magnitude and...
Types: Citation;
Tags: Earthquake Hazards Program,
GHSC,
Geologic Hazards Science Center,
ShakeMap,
USGS,
New active-source shallow seismic (shear-wave and acoustic-wave) measurements were obtained at 18 prioritized seismic monitoring station locations in the north San Francisco Bay area to measure site-specific ground motion amplification effects, soil depth, depth to bedrock (Z1.0 Vs=1 km/s), calculate site specific velocity-depth profiles and Vs30, and develop NEHRP site classifications for each location. This study was led by Principal Investigators Jamey Turner, Cooper Brossy, and Daniel O’Connell and field data were acquired by Glendon Adams and Lincoln Steele. Seismic monitoring sites that recorded high PGA values during the M6.0 Napa earthquake, proximal to higher population densities, and sites recommended...
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
EHP,
Earthquake Hazards Program,
GHSC,
Geologic Hazards Science Center,
The NEIC global earthquake bulletin is called the Preliminary Determination of Epicenters or PDE, and is one of many discrete products in the ANSS Comprehensive Catalog (ComCat). We use the word "Preliminary" for our final bulletin because the Bulletin of the International Seismological Centre is considered to be the final global archive of parametric earthquake data, in other words phase arrival (“pick”) times and amplitudes.
Types: Citation;
Tags: ANSS,
Advanced National Seismic System,
ComCat,
Comprehensive Earthquake Catalog,
Earth,
Note: This data release has been superseded, available here: https://doi.org/10.5066/P9MYL7WJ This data release contains processed high-resolution multichannel sparker seismic-reflection (MCS) data that were collected aboard Humboldt State University’s R/V Coral Sea in October of 2018 on U.S. Geological Survey cruise 2018-658-FA on the shelf and slope between Cape Blanco, Oregon, and Cape Mendocino, California. MCS data were collected to characterize quaternary deformation and sediment dynamics along the southern Cascadia margin.
Multichannel minisparker and boomer seismic-reflection and chirp sub bottom data were collected by the U.S. Geological Survey in September of 2013 in Port Valdez, Alaska. Data were collected aboard the USGS R/V Alaskan Gyre during field activity G-01-13-GA. Sub-bottom acoustic penetration spans several hundreds of meters and is variable by location. High-resolution multichannel seismic-reflection data were acquired to support the U.S. Geological Survey Alaska coastal and marine hazards project to explore the sedimentary structure of tsunamigenic landslide deposits around an IODP drill site in Port Valdez. These data and information are intended for science researchers, students from elementary through college, policy...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Geophysics,
Seismology,
Structural Geology
High-resolution acoustic backscatter data, bathymetry data, single channel minisparker seismic-reflection data were collected by the U.S. Geological Survey (USGS) and the Alaska Department of Fish and Game in May of 2014 southwest of Chenega Island and southwest of Montague Island, Alaska. Data were collected aboard the Alaska Department of Fish and Game vessel, R/V Solstice, during USGS field activity 2014-622-FA, using a pole mounted 100-kHz Reson 7111 multibeam echosounder, a 500 Joule SIG 2-mille minisparker sound source and a single channel streamer.
Supplemental Material: Distinct yet adjacent earthquake sequences near the Mendocino Triple Junction: 20 December 2021 Mw 6.1 and 6.0 Petrolia, and 20 December 2022 Mw 6.4 Ferndale Data Sets S0-S4 with station data and earthquake catalogs in text format See README_Data_Supplement.pdf for more details
Compressional- (P-) wave seismic refraction data were acquired in December 2018 and July 2019 along fourteen profiles within the spillway of Success Dam in Porterville, California. A new concrete ogee weir is planned for construction within the existing spillway, and the P-wave seismic velocity models will be used to inform further geotechnical investigations, including siting new geologic borings, and the advanced engineering design phases in terms of rock rippability and relative rock hardness/competency. Data acquisition, processing, and modeling were conducted collaboratively between the U.S. Geological Survey (USGS) and U.S. Army Corps of Engineers (USACE) Sacramento District. Data were acquired with Geometrics...
Categories: Data;
Tags: California,
GGGSC,
Geology, Geophysics, and Geochemistry Science Center,
Lake Success,
Porterville,
The data set consists of time, depth, reflection coefficient synthetic, sonic velocity, density, and amplitude used to create synthetic seismogram - City of Hollywood Utility, G-2961, (HOL-IW1), Broward County, Florida.
Categories: Data;
Types: Citation;
Tags: Broward County,
Miami-Dade County,
USA,
United States,
data preservation,
The data set consists of text files used to create the synthetic seismogram - City of Miramar, G-2946, (IW-2), Broward County, Florida.
Categories: Data;
Types: Citation;
Tags: Broward County,
Miami-Dade County,
USA,
United States,
data preservation,
This digital elevation model provides a tool for calibrating tsunami risk to observations of the 1945 Makran tsunami in Karachi Harbour. The DEM bathymetry is derived from soundings made mainly during the first eight years after the tsunami. Although deficient in portraying intertidal backwaters and upland topography, the DEM accurately depicts the sheltered setting of one of the two tide gauges that recorded the 1945 tsunami.
Categories: Data;
Types: Downloadable,
GeoTIFF,
Map Service,
Raster;
Tags: Geography,
Geomorphology,
Geophysics,
Marine Geology,
Seismology,
This dataset consists of an inventory of the locations of liquefaction-related phenomena triggered by the 7 January 2020 M6.4 Puerto Rico earthquake. The inventory is primarily based on field observations collected during post-earthquake reconnaissance conducted by the USGS and partners (Allstadt and others, 2020, Interactive Dashboard). Some additional locations were added based on reconnaissance reports by other groups (Miranda and others, 2020; Morales-Velez and others, 2020). We delineated 43 polygons of liquefaction areas and lateral spreading where we had sufficient evidence to do so (liquefaction_polygons_20210913.zip), but all outlines are approximate because liquefaction is primarily a subsurface process...
Near-surface site characteristics are critical for accurately modeling ground motion, which in turn influences seismic hazard analysis and design of critical infrastructure. Currently, there are many strong motion accelerometers within the Advanced National Seismic System (ANSS) that are missing this information. We use a Geographic Information Systems (GIS) based framework to intersect the site coordinates of approximately 5,500 ANSS accelerometers located throughout the United States and its territories with geology and velocity information. We consider: (1) surficial geology from digitized geologic maps (Horton, 2017; Wilson et al., 2015; Sherrod et al., 2007; Bawiec, 1999; Saucedo, 2005; Bedrossian et al., 2012;...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: ANSS,
Alabama,
American Samoa,
Arizona,
Arkansas,
Subduction zones are home to the most seismically active faults on the planet. The shallow megathrust interface of subduction zones host our largest earthquakes, and are the only faults capable of M9+ ruptures. Despite these facts, our knowledge of subduction zone geometry - which likely plays a key role in determining the spatial extent and ultimately the size of subduction zone earthquakes - is incomplete. Here we calculate the three- dimensional geometries of all active global subduction zones. The resulting model - Slab2 - provides for the first time a comprehensive geometrical analysis of all known slabs in unprecedented detail. ##### This distribution includes models of three-dimensional slab geometry under...
This dataset accompanies planned publication 'Determining fault geometry through the transport-parallel distribution of thermochronometer cooling ages'. The Ar/Ar data is for samples that record the thermal history of the area. The geochronology provides time constraints for the thermal histories studied in the manuscript. Samples were collected from Nepal, overseen by Nadine McQuarrie (University of Pittsburgh), who sent them to the USGS Denver Argon Geochronology Laboratory for Ar/Ar analysis.
Categories: Data;
Tags: 40Ar/39Ar,
Argon Geochronology Laboratory,
GGGSC,
Geochemistry,
Geology, Geophysics, and Geochemistry Science Center,
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...
In this database, we compile and host several available onshore and offshore geologic, paleoseismic, geophysical, and instrumental datasets along the Cascadia subduction zone. The ScienceBase data release and downloadable map package is accompanied by an ArcGIS online map and StoryMap.
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Geomorphology,
Geophysics,
Marine Geology,
Remote Sensing,
Sedimentology,
The 2018 Kīlauea eruption and caldera collapse generated intense cycles of seismicity tied to repeated large seismic (Mw ~5) collapse events associated with magma withdrawal from beneath the summit. To gain insight into the underlying dynamics and aid eruption response, we applied waveform-based earthquake detection and double-difference location as the eruption unfolded. Here, we augment these rapid results by grouping events based on patterns of correlation-derived phase polarities across the network. From April 29 to August 6, bracketing the eruption, we used ~2800 events cataloged by the Hawaiian Volcano Observatory to detect and precisely locate 44,000+ earthquakes. Resulting hypocentroids resolve complex,...
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