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The 2023 Update of the Alaska National Seismic Hazard Model: Overview and Sensitivities

Description: 

The 2023 update for the U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) for the state of Alaska includes updates to the seismic source model (SSM), or earthquake rupture forecast (ERF), and ground motion model (GMM) components. These updates incorporate new data and models gathered and developed since the previous update in 2007. The SSM is updated with an expanded crustal fault inventory and considers both geologic and geodetic rate models and includes several zone sources in key areas. Crustal and subduction gridded seismicity component rate models, based on an updated earthquake catalog that includes events from 2007 to 2020, incorporate multiple methods for declustering the catalog and smoothing spatial seismicity. Intraslab and small-magnitude interface sources are modeled with depths derived from the Slab2 (Hayes, 2018) geometry for the Alaska-Aleutian arc. The large-magnitude subduction interface model uses updated megathrust segmentation and model geometry (based on Slab2), and includes geologic, geodetic, and earthquake catalog derived earthquake rates. The 2023 NSHM for Alaska incorporates the NGA-West2 GMMs for crustal sources and the NGA-Subduction GMMs with Alaska-specific regionalization for both interface and intraslab sources. We present an overview of the preceding updates in the 2023 NSHM for Alaska, sensitivity calculations, and comparisons to the previous update in 2007.

Session: USGS National Seismic Hazard Models: 2023 and Beyond [Poster]

Type: Poster

Date: 4/18/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Jason M. Altekruse

Student Presenter: No

Invited Presentation: 

Authors