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Physics-based Seismic Hazard Assessment Using Multi-cycle Earthquake Simulations: Influence of Segment Connectivity and Strength Distribution

Description: 

During the past decades, numerous seismic hazard assessment (SHA) studies have been conducted to help mitigate earthquake-related casualties and economic losses. However, the short instrumental period of recorded earthquakes poses a challenge to accurately estimate the recurrence rates of potentially hazardous earthquakes. Hence, a rigorous SHA should not rely solely on past seismic events or on deterministic extreme scenarios. Instead, novel approaches such as numerical multi-cycle rupture simulations producing synthetic seismic catalogs can be used to enhance the reliability of the SHA.

The mega-project of NEOM, located within the seismic active region of the gulf of Aqaba (GoA), the southern extension of the Dead Sea fault zone, has attracted increased scientific attention due to the region’s susceptibility to large-magnitude earthquakes (e.g., 1995 M7.3 Nuweiba earthquake). Therefore, we conduct physics-based simulations using a multi-cycle engine (MCQsim) to create long-term synthetic seismic catalogs. We model different seismic-source realizations varying the spatial gaps among the strike-slip segments as well as the strength distribution throughout the complex fault system of the GoA. The resulting synthetic catalogs provide a possible pathway to quantify epistemic uncertainties that arise from poorly constrained parameter space (e.g., fault geometry and frictional strength). By analyzing MCQsim catalogs spanning tens-of-thousands of years, we infer the recurrence rates and complex patterns of multi-segment ruptures. Furthermore, we establish a workflow to incorporate these rupture scenarios into the probabilistic seismic hazard assessment framework of OpenQuake to compute exceedance probabilities of different ground-motion intensity measures. Our findings indicate that both spatial fault continuity and strength distribution affect the resulting long-term multi-cycle catalogs and hence have a measurable impact on peak ground accelerations and uniform hazard spectra.

Session: Regional-Scale Hazard, Risk and Loss Assessments [Poster Session]

Type: Poster

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Theodoros

Student Presenter: Yes

Invited Presentation: 

Authors