RSQSim Earthquake Simulator

Abstract

As discussed in Tullis et al. (2012b), a promising avenue for improving seismic hazard estimation and reducing the large uncertainties in current assessments is to incorporate more accurate and region‐specific characterizations of the interactions and physical processes that control earthquake occurrence in fault systems. Earthquake simulators are computer models that can contribute to this by carrying out large‐scale simulations of earthquake occurrence to characterize system‐level response of fault systems including processes that control time, place, and extent of earthquake slip. Such simulators were pioneered by work such as Rundle (1988), Robinson and Benites (1995), and Ward (1996). Four such simulators are discussed in the November/December 2012 Seismological Research Letters issue, and their general features are described in Tullis et al. (2012a). This paper describes features specific to one of those four, RSQSim. It also presents results that are relevant to particularly unique features of RSQSim: comparisons with fully dynamic single‐event simulations and the spatial‐temporal clustering of seismicity due to RSQSim’s use of rate‐ and state‐dependent friction (RSF). RSQSim is based on a scheme initially developed by Dieterich (1995) with several enhancements to extend its use in a number of directions including allowing fully general fault system geometries and the attendant normal stress variations, better validation of the quasi‐dynamic part of the seismic cycle against fully dynamic models, and the inclusion of creeping parts of the fault system. Ziv (2003) and Ziv and Rubin (2003) used some elements of the original method to study clustering processes and frequency statistics. RSQSim itself has been used by Dieterich and Richards‐Dinger (2010) to study the effects of both small‐ and large‐scale fault system geometry on recurrence statistics in a idealized but complex fault system. We do not discuss it further here, but RSQSim has also been used successfully to model slow …