Ground Motion Models for the Island of Hawaii Using the Hybrid Empirical Method

Session: Forthcoming Updates of the USGS NSHMs: Hawaii, Conterminous U.S. and Alaska [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The main purpose of this study is to develop Ground Motion Models (GMMs) for the island of Hawaii using the Hybrid Empirical Method (HEM). Stochastically simulated Ground Motion Intensity Measures (GMIMs) in the host and target regions are utilized in HEM to develop adjustment factors that are applied to empirical GMIM predictions in the host region.  The island of Hawaii, the target region in this study, has been the site of numerous large earthquakes with a growing database of strong ground motion observations. The crustal earthquakes in the island of Hawaii originate from volcanic activity and include both swarms of small-magnitude volcanic events and larger tectonic events. Ground motion modeling of the island of Hawaii is challenging due to the depth distribution of events and different anelastic attenuation characteristics. However, only a few GMMs have been developed for the island of Hawaii, which suffer from several limitations. The applicability of HEM to develop GMMs for the island of Hawaii and the growing strong ground motion data will result in further improvements in the capability of GMMs. Since the seismic hazard comes both from shallow crustal earthquakes and from deep events for the island of Hawaii, we propose to develop two separate GMMs. Following the Hawaii State hazard maps, we will consider the focal depth of 20 km to distinguish between shallow crustal and deep earthquakes (Klein et al., 2001). The proposed GMMs will be derived for the 5%-damped pseudo-acceleration linear-elastic response spectra for a reference rock site with V_S30 = 760 m/sec similar to the shear-wave velocity in the near-surface for lava sites in the island of Hawaii (about 600 m/sec). A moment magnitude range of 4.0 to 7.5 and Joyner-Boore distances of up to 400 km will be considered. This research supplements previously developed GMMs for the island of Hawaii considering a different methodology and an updated strong ground motion database.

Presenting Author: Alireza Haji-Soltani

Authors