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The 2023 Update of the Alaska National Seismic Hazard Model

Description: 

The U.S. Geological Survey (USGS) is developing a major revision to the Alaska portion of the 2023 National Seismic Hazard Model (NSHM). This update will incorporate new data and models that have been gathered and published since the last update to the Alaska NSHM in 2007. The 2023 Alaska NSHM includes updates to both source, or earthquake rupture forecast (ERF), and ground motion model (GMM) components. The ERF includes updates to the crustal fault inventory and considers both geologic and geodetic rate models. The large-magnitude subduction interface model uses an updated segmentation and structural model (based on the SLAB2 geometry of the Alaska-Aleutian arc) and includes geologic, geodetic, and earthquake catalog-derived earthquake rates. A new catalog that includes earthquakes from 2007 to 2020 has been compiled to inform the rate model for the both the crustal and subduction gridded seismicity components. Calculation of the gridded seismicity rate models considers multiple declustering and smoothing methods and subduction interface (small magnitude) and intraslab sources are modeled at depths derived from SLAB2. For the GMM component, the model uses the new NGA-Subduction GMMs with regionalization for Alaska for both interface and intraslab sources and the NGA-West2 GMMs for crustal sources. Here we present implementation details of the above model components and comparisons to the prior NSHM from 2007.

Session: USGS National Seismic Hazard Models: 2023 and Beyond

Type: Oral

Date: 4/18/2023

Presentation Time: 09:00 AM (local time)

Presenting Author: Peter M. Powers

Student Presenter: No

Invited Presentation: 

Authors