Cascadia-Specific NGA-Subduction Ground Motion Models for Interface and Intraslab Events with Regionalized Site Response

Date: 4/24/2019

Time: 11:15 AM

Room: Pine

The Next Generation Attenuation – Subduction Project is a multi-year, multidisciplinary research project that is compiling processed ground motion recordings and the associated metadata from subduction zone events and developing a suite of semi-empirical ground motion models. Earthquake data came from Alaska, the Aleutian Islands, and the Cascadia subduction zone in the Pacific Northwest region of the United States, British Columbia, Mexico, Chile, Peru, Ecuador, Japan, Taiwan, and New Zealand. Some terms of the ground-motion prediction equations were regionalized due to observed differences between subduction zones including the intercept, anelastic attenuation, magnitude-scaling breakpoint, V_S30-scaling, and basin terms. We describe the process by which our model was developed, including these regional adjustments for source, path, and site effects. More specifically, this presentation emphasizes regional features of the ground motions in the Cascadia region for both interface and intraslab events. This includes an investigation of regional V_S30-scaling, and basin effects specific to the Seattle, Tacoma, Everett, Tualatin and Portland basins (Ahdi et al. 2019). We also make comparisons to the global NGA-Subduction models, and validate the regional model against ground motions from empirical events recorded in Cascadia, and broadband simulations for the region.

Presenting Author: Grace A. Parker

Authors