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The 2017 USGS South American seismic hazard model is based on: a uniform seismicity catalog, a smoothed (gridded) seismicity model, a subduction model, crustal fault model, and ground motion models that are described below. These models are combined to account for ground shaking from earthquakes on known faults as well as earthquakes on faults not included in the model.
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This maps portrays the spatial potential for damaging earthquake ground shaking quantified as moderate (MMI ≥ VII) in 100 years. The maps and data are based on the average of the results obtained from peak ground acceleration and 1.0-second horizontal spectral acceleration. Site specific soil factors based on Vs30 shear wave velocities were implemented using a simple topographic proxy technique (Allen and Wald, 2009) and site amplification based on the relationships of Seyhan and Stewart (2014). MMI ≥ VII is equivalent to peak ground acceleration of 0.22g and 1.0-second horizontal spectral acceleration of 0.23g (Worden et al., 2012). Allen, T.A. and Wald, D.J. 2009,. On the use of high-resolution topographic...
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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...
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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 Modified Mercalli Intensity with a 2 percent probability of exceedance in 50 years. The maps and data were derived from PGA ground-motion conversions of Worden et al. (2012), and include soil amplification...
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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 10 percent probability of exceedance in 50 years.
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 hazard curves for a grid of points with a spacing of 0.1 degrees in latitude and longitude. It represents the annual rate of exceedance versus peak ground acceleration.
These maps and data portray the spatial potential for damaging ground shaking quantified as slight (MMI ≥ VI), moderate (MMI ≥ VII), and considerable (MMI ≥ VIII) in 100 years. The maps and data are based on the average of the results obtained from pga and 1.0-second horizontal spectral acceleration. Site specific soil factors based on Vs30 shear wave velocities were implemented using a simple topographic proxy technique (Allen and Wald, 2009). Allen, T.A. and Wald, D.J. 2009,. On the use of high-resolution topographic data as a proxy for seismic site conditions (VS30), Bulletin of the Seismological Society of America 99, 935-943.
The probabilistic hazard models are used in conjunction with the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) empirical vulnerability relationships (Jaiswal and Wald, 2010, 2011) to calculate seismic risk. The vulnerability relationships are country specific and were used to estimate fatalities and economic losses from earthquake ground shaking. These relationships are highly approximate and are a proxy approach to quantifying earthquake losses. Accuracy can vary by an order of magnitude for places that lack empirical loss data. Jaiswal, K. S., and Wald, D.J., 2010, An empirical model for global earthquake fatality estimation, Earthquake Spectra 26, 1017-1037. Jaiswal, K. S., and Wald,...
In develpoing the hazard model for South America, the USGS considered the ground motion models (GMM) used for the conterminous United States because most of the equations consider global earthquakes and because the U.S. and South America are seismically quite similar, with the potential for active subduction, deep intraslab, crustal, and craton earthquakes. Included here is a table that summarizes the GMMs selected for each of the earthquake types and the weight applied within the model.
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This maps portrays the spatial potential for damaging earthquake ground shaking quantified as considerable (MMI ≥ VIII) in 100 years. The maps and data are based on the average of the results obtained from peak ground acceleration and 1.0-second horizontal spectral acceleration. Site specific soil factors based on Vs30 shear wave velocities were implemented using a simple topographic proxy technique (Allen and Wald, 2009) and site amplification based on the relationships of Seyhan and Stewart (2014). MMI ≥ VIII is equivalent to peak ground acceleration of 0.40g and 1.0-second horizontal spectral acceleration of 0.50g (Worden et al., 2012). Allen, T.A. and Wald, D.J. 2009,. On the use of high-resolution topographic...
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This maps portrays the spatial potential for damaging earthquake ground shaking quantified as slight (MMI ≥ VI) in 100 years. The maps and data are based on the average of the results obtained from peak ground acceleration and 1.0-second horizontal spectral acceleration. Site specific soil factors based on Vs30 shear wave velocities were implemented using a simple topographic proxy technique (Allen and Wald, 2009) and site amplification based on the relationships of Seyhan and Stewart (2014). MMI ≥ VI is equivalent to peak ground acceleration of 0.12g and 1.0-second horizontal spectral acceleration of 0.1g (Worden et al., 2012). Allen, T.A. and Wald, D.J. 2009,. On the use of high-resolution topographic data...
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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 Modified Mercalli Intensity with a 10 percent probability of exceedance in 50 years. The maps and data were derived from PGA ground-motion conversions of Worden et al. (2012), and include soil amplification...
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The 2021 update of the U.S. National Seismic Hazard Model for Hawaii succeeds the twenty-year-old former model by incorporating new data and modeling techniques to improve the ground shaking forecasts. Output from the model 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 between 0.01 and 10 second, and for eight separate soil site classes (VS30 = 1500 m/sec to 150 m/sec), representing NEHRP site classes A/B to E. In addition, gridded uniform- hazard data are provided...
The Atlas of ShakeMaps (~14,100 earthquakes, 1900-2020) provides a consistent and quantitative description of the distribution of shaking intensity for calibrating earthquake loss estimation methodologies, like those used in the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system. Version 4 of the Atlas includes a vastly expanded compilation of ShakeMaps for consequential and widely felt earthquakes using updated ShakeMap (Version 4) software. For each event, we have attempted to gather available macroseismic, recorded ground motions and finite fault inputs. AtlasCat is the companion catalog to Atlas V4. For each event in the Atlas, AtlasCat contains population exposure to each intensity level,...
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Expected average annual losses from earthquakes are determined by using PAGER's vulnerability functions that are unique to each country. There are significant differences in economic losses between countries, which is indicative of their relative vulnerability to earthquakes.
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These data were calculated to estimate seismic hazard, risk, and design across South America using the latest data, models, and methods. The input data to the model, as well as the output data are available here. The input data includes a seismicity catalog, seismicity rate models, evaluation of earthquake sizes, fault geometry and rate parameters, and ground-motion models. Output data include hazard curves, and associated products, for peak ground acceleration and spectral accelerations at 0.2 and 1 s periods.
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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 2 percent probability of exceedance in 50 years.
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 hazard curves for a grid of points with a spacing of 0.1 degrees in latitude and longitude. It represents the annual rate of exceedance versus 1.0-second spectral response acceleration.
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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 50 percent probability of exceedance in 50 years.
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Expected average annual fatalities from earthquakes are determined by using PAGER's vulnerability functions that are unique to each country. There are significant differences in fatality rates between countries, which is indicative of their relative vulnerability to earthquakes.