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This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.05 degrees in latitude and longitude. This particular data set is for horizontal spectral response acceleration for 0.2-second period with a 1 percent probability of exceedance in 1 year. The data are for the Western United States and are based on the long-term 2014 National Seismic Hazard Model.
A comparison of the 2017 USGS South America seismic hazard model with the Global Seismic Hazard Assessment Program (GSHAP) model and the 2010 USGS preliminary model was made to see how the models differ. The comparisons were made as ratios of PGA at 10% probability of exceedance in 50 years. Ratio maps of each comparison are included as a geo-referenced tiff (GeoTIFF).
These data sets are the results of calculations of hazard curves for a grid of points with a spacing of 0.05 degrees in latitude and longitude. They represent the chance of experiencing potentially damaging ground shaking for fixed ground shaking levels that corresponds with MMI = VII. The values are obtained by averaging the probability of experiencing MMI = VII based on a peak ground acceleration value of 0.2152 g for site class D, and the probability of experiencing MMI = VII based on 1.0-second spectral acceleration value of 0.2256 g for site class D. The data are for the Central and Eastern United States.
It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (http://pubs.usgs.gov/of/2012/1088; page 32), the USGS currently lacks an automated system with which to forecast such events and official protocols for disseminating the potential implications. This capability, known as Operational Earthquake Forecasting (OEF), could provide valuable situational awareness to emergency managers, the public, and other entities interested in preparing for potentially damaging earthquakes. With the various...
Categories: Data,
Project;
Tags: Active,
All Working Groups,
California,
Earthquakes,
Natural Hazards
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,
A seismic hazard model for South America, based on a smoothed (gridded) seismicity model, a subduction model, a crustal fault model, and a ground motion model, has been produced by the U.S. Geological Survey. These models are combined to account for ground shaking from earthquakes on known faults as well as earthquakes on un-modeled faults. This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.1 degrees in latitude and longitude. This particular data set is for peak ground acceleration with a 10 percent probability of exceedance in 50 years.
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Argentina,
Bolivia,
Brazil,
Chile,
Colombia,
A seismic hazard model for South America, based on a smoothed (gridded) seismicity model, a subduction model, a crustal fault model, and a ground motion model, has been produced by the U.S. Geological Survey. These models are combined to account for ground shaking from earthquakes on known faults as well as earthquakes on un-modeled faults. This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.1 degrees in latitude and longitude. This particular data set is for horizontal spectral response acceleration for 0.2-second period with a 50 percent probability of exceedance in 50 years.
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Argentina,
Bolivia,
Brazil,
Chile,
Colombia,
A seismic hazard model for South America, based on a smoothed (gridded) seismicity model, a subduction model, a crustal fault model, and a ground motion model, has been produced by the U.S. Geological Survey. These models are combined to account for ground shaking from earthquakes on known faults as well as earthquakes on un-modeled faults. This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.1 degrees in latitude and longitude. This particular data set is for horizontal spectral response acceleration for 1.0-second period with a 10 percent probability of exceedance in 50 years.
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Argentina,
Bolivia,
Brazil,
Chile,
Colombia,
Seismic hazard curves were determined using the USGS seismic hazard model for South America. The curves represent the annual rate of exceedance versus peak horizontal acceleration or horizontal spectral response acceleration for 0.2- or 1.0-second periods, for a grid of points with a spacing of 0.1 degrees in latitude and longitude. The hazard curves were used to prepare maps and gridded data that portray peak horizontal acceleration and horizontal spectral response acceleration for 0.2- and 1.0-second periods with a 2%, 10%, and 50% probability of exceedance in 50 years, and a uniform site condition (Vs30) of 760 m/sec. MMI maps for 2%, 10%, and 50% probability of exceedance in 50 years were derived from PGA...
A comparison of the 2021 and 2001 National Seismic Hazard Models (NSHMs) for Hawaii was performed by creating difference and ratio maps for a uniform-hazard with a 2% probability of excedance in 50 years, for spectral accelerations at 0.2 and 1.0 second periods. The data are for a reference site condition of Vs30 equal to 760 m/s. A similar comparison between the ground-motion models (GMMs) used in 2021 versus 2001 was performed by running the 2021 NSHM with the 2001 GMMs. The maps and gridded data used to make the maps are available here for download.
Categories: Data
This dataset presents where, why, and how much probabilistic ground motions have changed with the 2018 update of the National Seismic Hazard Model (NSHM) for the conterminous U.S. (CONUS) vs. the 2014 NSHM. In the central and eastern U.S., hazard changes are the result of updated ground motion models (further broken down by median and epistemic uncertainty, aleatory variability, and site effects models) and gridded seismicity models. In the western U.S., hazard changes are the result of updated ground motion models in four urban areas with deep sedimentary basins and gridded seismicity models. Probabilistic ground motion changes (2% in 50 years probability of exceedance for a firm rock site, VS30 = 760 m/s, NEHRP...
Categories: Data;
Tags: Conterminous U.S.,
EHP,
Earthquake Hazards Program,
GHSC,
Geologic Hazards Science Center,
This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.05 degrees in latitude and longitude. It represents the average Modified Mercalli Intensity (MMI) with a 1-percent probability of exceedance in 1 year. Using a topographic-based soil classification method, the ground motions are amplified for soil type. The MMI values are the average of the MMI values obtained by converting peak ground acceleration to MMI and 1.0-second spectral response acceleration to MMI. The data are for the Western United States and are based on the long-term 2014 National Seismic Hazard Model.
This data set represents the results of calculations of hazard curves for a grid of points with a spacing of 0.05 degrees in latitude and longitude. This particular data set is for horizontal spectral response acceleration for 1.0-second period with a 1 percent probability of exceedance in 1 year. The data are for the Western United States and are based on the long-term 2014 National Seismic Hazard Model.
5. Declustered seismicity catalogs used in the 2018 update of the U.S. National Seismic Hazard Model
An updated, declustered seismicity catalog is assembled from several preexisting catalogs. The methodology developed by Mueller (2019) was used to convert original magnitudes to uniform moment magnitudes, delete duplicate events, delete non-tectonic events, and finally decluster the catalog.
A comparison of the 2017 USGS South America seismic hazard model and the 2010 USGS preliminary model was made to see how the models differ. The comparison was made as the ratio of PGA at 10% probability of exceedance in 50 years. The ratio map is included here as a geo-referenced tiff (GeoTIFF). The gridded data for the 2017 PGA at 10% probability can be found here, while the gridded data for the 2010 PGA at 10% probability can be found in the zip archive that can be downloaded using a link on this page.
Categories: Data;
Types: Citation,
Downloadable,
GeoTIFF,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Raster,
Shapefile;
Tags: Argentina,
Bolivia,
Brazil,
Chile,
Colombia,
Maximum considered earthquake geometric mean peak ground acceleration maps (MCEG) are for assessment of the potential for liquefaction and soil strength loss, as well as for determination of lateral earth pressures in the design of basement and retaining walls. The maps are derived from the USGS seismic hazard maps in accordance with the site-specific ground-motion procedures of the NEHRP Recommended Seismic Provisions for New Building and Other Structures and the ASCE Minimum Design Loads for Buildings and Other Structures (also known as the ASCE 7 Standard; ASCE, 2016). The MCEG ground motions are taken as the lesser of probabilistic and deterministic values, as explained in the Provisions. The gridded probabilistic...
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Argentina,
Bolivia,
Brazil,
Chile,
Colombia,
A comparison of the 2017 USGS South America seismic hazard model and the Global Seismic Hazard Assessment Program (GSHAP) model was made to see how the models differ. The comparison was made as the ratio of PGA at 10% probability of exceedance in 50 years. The ratio map is included here as a geo-referenced tiff (GeoTIFF). The gridded data for the 2017 PGA at 10% probability can be found here, while the GSHAP data can be found here. Shedlock, K.M., Giardini, Domenico, Grünthal, Gottfried, and Zhang, Peizhan, 2000, The GSHAP Global Seismic Hazar Map, Sesimological Research Letters, 71, 679-686. https://doi.org/10.1785/gssrl.71.6.679
Categories: Data;
Types: Citation,
Downloadable,
GeoTIFF,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Raster,
Shapefile;
Tags: Argentina,
Bolivia,
Brazil,
Chile,
Colombia,
The crustal fault model accounts for earthquakes that occur on faults that have not ruptured recently, but have have been active in historic and prehistoric periods. Although hundreds of Quaternary faults have been mapped, only a few of these faults have been studied sufficiently to reach a consensus regarding rate of deformation that can be applied in this hazard assessment. Information regarding the seismogenic source geometry and seismogenic source behavior that is necessary to model each fault is included for each fault. Files that can be used as input to computer hazard code are included.
Output from the 2021 National Seismic Hazard Model for Hawaii includes probabilistic seismic hazard curves calculated for a 0.02° x 0.02° grid of latitude/longitude locations across Hawaii. The new model provides an expanded suite of hazard curves for twenty-three different ground motion intensity measures, including PGA, PGV, and spectral accelerations for 0.01, 0.02, 0.03, 0.05, 0.075, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.75, 1, 1.5, 2, 3, 4, 5, 7.5 and 10 second, and eight separate soil site classes (VS30 = 1500, 1080, 760, 530, 365, 260, 185, and 150 m/sec), representing NEHRP site classes A/B, B, B/C, C, C/D, D, D/E, and E. This data set represents the hazard curves for a grid of points with a spacing...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Earthquake,
Hawaii,
Hazard,
Seismic
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