Foreign Hazard Maps

Science Center Objects

  

Afghanistan

Gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2007 Afghanistan Seismic Hazard Model. Probabilistic seismic hazard data and maps of Afghanistan for peak ground acceleration (PGA) and 0.2 and 1.0 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 Afghanistan Seismic Hazard Model is documented in the USGS Open-File Report 2007-1137.

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.

Haiti

Gridded seismic hazard curve data, gridded ground motion data, and mapped gridded ground motion values are available for the 2010 Haiti Seismic Hazard Model. Probabilistic seismic hazard data and maps are available for peak ground acceleration (PGA) and 0.2, and 1.0 second spectral acceleration at probability levels of 2 percent in 50 years and 10 percent in 50 years, assuming firm rock soil conditions at 760 m/s. Development of the 2010 Haiti Seismic Hazard Model is documented at Documentation for Initial Seismic Hazard Maps for Haiti and Seismic Hazard Maps for Haiti.

South America

The USGS has developed a preliminary seismic hazard model using available seismic catalogs, fault databases, and hazard methodologies to help facilitate discussions and to ascertain data requirements and availability. This preliminary seismic hazard model follows the methodology that was developed by the USGS for the United States (Petersen et al., 2008). The SASHA source model includes a smoothed seismicity component applied across the entire continent that accounts for earthquakes M 5-7, subduction zone sources M 7-9.5, and crustal faults M7-8. The primary tectonics for this region involve subduction of the Nazca plate beneath the west portion of the South American plate with related interface and intra-slab earthquakes and shallow crustal earthquakes.

Southeast Asia

The ground motion hazard for Sumatra and the Malaysian peninsula is calculated in a probabilistic framework, using procedures developed for the US National Seismic Hazard Maps. We constructed regional earthquake source models and used standard published and modified attenuation equations to calculate peak ground acceleration at 2% and 10% probability of exceedance in 50 years for rock site conditions. We developed or modified earthquake catalogs and declustered these catalogs to include only independent earthquakes. The resulting catalogs were used to define four source zones that characterize earthquakes in four tectonic environments: subduction zone interface earthquakes, subduction zone deep intraslab earthquakes, strike-slip transform earthquakes, and intraplate earthquakes.

State of Gujarat, India

We test the sensitivity of seismic hazard to three fault source models for the northwestern portion of Gujarat, India. The models incorporate different characteristic earthquake magnitudes on three faults with individual recurrence intervals of either 800 or 1600 years. These recurrence intervals imply that large earthquakes occur on one of these faults every 266—533 years, similar to the rate of historic large earthquakes in this region during the past two centuries and for earthquakes in intraplate environments like the New Madrid region in the central United States.

 

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