Gridded ground motion data and mapped gridded ground motion values are available for the 1999 Alaska Seismic Hazard Model. Probabilistic seismic hazard data and maps of Alaska and the Aleutians for peak ground acceleration (PGA) and 0.2, 0.3, and 1.0 second spectral acceleration at probability levels of 2 percent in 50 years (annual probability of 0.000404) and 10 percent in 50 years (annual probably of 0.0021), assuming firm rock soil conditions at 760 m/s, are available. Development of the 1999 Alaska Seismic Hazard Model is documented in the USGS Open-File Report 99-36 (https://doi.org/10.3133/ofr9936). This dataset is considered a legacy dataset. The original dataset was uploaded to the USGS website at the time of publication of the seismic hazard model (1999) but was later moved over the the USGS ScienceBase Catalog (2019). The original dataset was assumed to be complete and accurate, but may contain inconsistencies when compared to more recent, actively maintained datasets.

Gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2007 Alaska Seismic Hazard Model. Time-independent probabilistic seismic hazard data and maps of Alaska and the Aleutians 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), 5 percent in 50 years (annual probability of 0.001026), and 10 percent in 50 years (annual probability of 0.0021) assuming firm rock soil conditions at 760 m/s are available. Development of the 2007 Alaska Seismic Hazard Model is documented in the USGS Open-File Report 2007-1043 (https://pubs.usgs.gov/of/2007/1043/). This dataset is considered a legacy dataset. The original dataset was uploaded to the USGS website at the time of publication of the seismic hazard model (2007) but was later moved over the the USGS ScienceBase Catalog (2019). The original dataset was assumed to be complete and accurate, but may contain inconsistencies when compared to more recent, actively maintained datasets.

Gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2007 Alaska Seismic Hazard Model. Time-independent probabilistic seismic hazard data and maps of Alaska and the Aleutians 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), 5 percent in 50 years (annual probability of 0.001026), and 10 percent in 50 years (annual probability of 0.0021) assuming firm rock soil conditions at 760 m/s are available. Development of the 2007 Alaska Seismic Hazard Model is documented in the USGS Open-File Report 2007-1043 (https://pubs.usgs.gov/of/2007/1043/). This dataset is considered a legacy dataset. The original dataset was uploaded to the USGS website at the time of publication of the seismic hazard model (2007) but was later moved over the the USGS ScienceBase Catalog (2019). The original dataset was assumed to be complete and accurate, but may contain inconsistencies when compared to more recent, actively maintained datasets.

This dataset represents probabilistic seismic hazard curves and uniform-hazard ground motion values calculated for a grid of points with a spacing of 0.2 degrees in latitude and longitude for the state of Alaska using the 2023 National Seismic Hazard Model (NSHM) for the state of Alaska. The dataset includes (1) probabilistic seismic hazard curves (full and truncated) for peak ground acceleration (PGA), and spectral acceleration for 0.2, 1.0, 2.0, and 5.0 seconds and (2) uniform-hazard ground motion values for 2, 5, and 10% in 50 years probability of exceedance (PE) (corresponding to 2,475, 975, and 475 year return periods, respectively) for each grid point. Results are provided for site classes BC and D, which correspond with Vs30s (time-averaged shear-wave velocity [VS] in the upper 30 m) of 760 and 260 m/s, respectively. Two different sets of hazard curves are available, full (curves.csv) and truncated (curves-truncated.csv). The full gridded hazard curves data include ground motions at long return periods, whereas the truncated curves only span return periods of 10,000 years (annual frequency of exceedance of 1.0E-04) and less. The National Seismic Hazard Models are not intended to provide ground motions at return periods longer than 10,000 years.

This dataset represents probabilistic seismic hazard curves and uniform-hazard ground motion values calculated for a grid of points with a spacing of 0.2 degrees in latitude and longitude for the state of Alaska using the 2023 National Seismic Hazard Model (NSHM) for the state of Alaska. The dataset includes (1) probabilistic seismic hazard curves (full and truncated) for peak ground acceleration (PGA), and spectral acceleration for 0.2, 1.0, 2.0, and 5.0 seconds and (2) uniform-hazard ground motion values for 2, 5, and 10% in 50 years probability of exceedance (PE) (corresponding to 2,475, 975, and 475 year return periods, respectively) for each grid point. Results are provided for site classes BC and D, which correspond with Vs30s (time-averaged shear-wave velocity [VS] in the upper 30 m) of 760 and 260 m/s, respectively. Two different sets of hazard curves are available, full (curves.csv) and truncated (curves-truncated.csv). The full gridded hazard curves data include ground motions at long return periods, whereas the truncated curves only span return periods of 10,000 years (annual frequency of exceedance of 1.0E-04) and less. The National Seismic Hazard Models are not intended to provide ground motions at return periods longer than 10,000 years.

The U.S. National Seismic Hazard Model (NSHM) for the state of Alaska was updated in 2023 as part of the 50-state NSHM update. The new model incorporates more than 15 years of additional science since the release of the previous model in 2007 and has been reviewed by a six-member review panel and a supplementary eight-member team of ground motion model developers. This time-independent probabilistic seismic hazard model applies new earthquake catalogs, declustering algorithms, gridded seismicity models, magnitude-scaling relations, geologic and geodetic deformation models, and ground motion models. This data release supports the 2023 Alaska NSHM and includes the seismicity catalogs used to develop the model, hazard curves and uniform-hazard ground motions for the state of Alaska, and multiple period response spectra for the Alaska test sites.

The U.S. National Seismic Hazard Model (NSHM) for the state of Alaska was updated in 2023 as part of the 50-state NSHM update. The new model incorporates more than 15 years of additional science since the release of the previous model in 2007 and has been reviewed by a six-member review panel and a supplementary eight-member team of ground motion model developers. This time-independent probabilistic seismic hazard model applies new earthquake catalogs, declustering algorithms, gridded seismicity models, magnitude-scaling relations, geologic and geodetic deformation models, and ground motion models. This data release supports the 2023 Alaska NSHM and includes the seismicity catalogs used to develop the model, hazard curves and uniform-hazard ground motions for the state of Alaska, and multiple period response spectra for the Alaska test sites.

The U.S. National Seismic Hazard Model (NSHM) for the state of Alaska was updated in 2023 as part of the 50-state NSHM update. The new model incorporates more than 15 years of additional science since the release of the previous model in 2007 and has been reviewed by a six-member review panel and a supplementary eight-member team of ground motion model developers. This time-independent probabilistic seismic hazard model applies new earthquake catalogs, declustering algorithms, gridded seismicity models, magnitude-scaling relations, geologic and geodetic deformation models, and ground motion models. This data release supports the 2023 Alaska NSHM and includes the seismicity catalogs used to develop the model, hazard curves and uniform-hazard ground motions for the state of Alaska, and multiple period response spectra for the Alaska test sites.

This dataset contains earthquake catalogs compiled for Alaska from U.S. Geolgical Survey (USGS) Advanced National Seismic System (ANSS) Comprehensive Earthquake Catalog (ComCat) (USGS, 2017) and Natural Resources Canada (NRCan) Canadian National Earthquake Database (NRCan, 1985) catalog searches and processed following the methods of Mueller (2019) and Llenos et al. (2024). Catalogs are deculstered using multiple methods and segregated into crustal, subduction interface, and subduction intraslab catalogs using Slab2 (Hayes, 2018).

The updated 2018 National Seismic Hazard Model includes new ground motion models, aleatory uncertainty, and soil amplification factors for the central and eastern U.S. and incorporates basin depths from local seismic velocity models in four western U.S. (WUS) urban areas. These additions allow us, for the first time, to calculate probabilistic seismic hazard curves for an expanded set of spectral periods (0.01 s to 10 s) and site classes (VS30 = 150 m/s to 1,500 m/s) for the conterminous U.S. (CONUS), as well as account for amplification of long-period ground motions in deep sedimentary basins in the Los Angeles, San Francisco Bay, Salt Lake City, and Seattle regions. Ground motion data for 2, 5, and 10 percent probability of exceedance in 50 years have been derived from these hazard curves.Two sets of data are available: (1) 0.05 by 0.05 degree gridded hazard data for the CONUS and (2) 0.01 by 0.01 degree gridded hazard data for WUS basins. Note that both sets of data contain basin amplification in deep sedimentary basins in the WUS. The 0.01 degree by 0.01 degree data simply provides a higher resolution dataset than then 0.05 degree by 0.05 degree dataset. This dataset is discussed in the journal article titled: "The 2018 update of the US National Seismic Hazard Model: Additional period and site class data" by Shumway et al. (2021) located at https://doi.org/10.1177/8755293020970979. First Posted - October 7, 2019 Revised - February 2020 (ver 1.1) Revised - May 2021 (ver 1.2)