← Back to Sessions

Recalibrating Earthquake Rupture Forecasts Using Long Catalogs From Multi-Cycle Earthquake Simulators

Description: 

Earthquake forecasting is of wide interest for the public, decision makers, and scientific community; however, the lack of long earthquake catalogs make the problem of calibrating forecasts difficult. Here, we develop an approach for assimilating the information from multi-cycle earthquake simulators into probabilistic rupture forecasts. We focus on recalibrating the time-independent Uniform California Earthquake Rupture Forecast Version 3 (UCERF3-TI) of Field et al. (2014) against long earthquake catalogs (~10⁶ years) generated by the multi-cycle Rate-State Quake Simulator (RSQSim) of Dieterich & Richards-Dinger (2010). We map ruptures from the RSQSim catalog of Shaw et al. (2018) onto equivalent UCERF3 ruptures by maximizing the mapping efficiency while preserving the seismic moment. This mapping process, sometimes called the association problem, sets the framework for utilizing data from diverse earthquake simulators and, should they be available, real earthquakes as well. We map RSQSim into UCERF3 following different rupture criteria, yielding different synthetic earthquake sub-catalogs. The statistics of these datasets remain nearly unchanged. Thus, our results show that RSQSim succeeds at representing the large earthquakes in UCERF3. Furthermore, we assume the sequence of equivalent UCERF3 ruptures is Poisson distributed and use the full UCERF3 logic tree to construct a joint prior distribution of rupture rates, which we represent by independent Gamma distributions. The differences in prior and posterior rates are attributed to the slip rate difference between RSQSim and UCERF3. Furthermore, our posterior model results in substantial lower rates in the Coachella, San Gorgonio, and San Bernardino San Andreas fault sections, reflecting the fact that RSQSim does not propagate ruptures through the San Gorgonio knot.

It is worthwhile stating that the results of this work are not intended to replace the current authoritative earthquake rupture forecasts, but to present a framework under which earthquake data is used to re-calibrate current models.

Session: Opportunities and Challenges in Source Modeling for Seismic Hazard Analysis [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Luis Vazquez

Student Presenter: Yes

Invited Presentation: 

Authors