Generic Earthquake Simulator

Many of the papers in this topical issue concern earthquake simulators and their results. The goals and history of the project leading to this work are described in the preface to this topical issue. Earthquake simulators are computer programs that use physics of stress transfer and frictional resistance to describe earthquake sequences. Some are capable of generating long earthquake histories on many faults. They necessarily adopt a variety of simplifications to make computation feasible. The amount of detail computed within individual earthquakes depends on the simulator. None of those capable of generating long histories includes elastodynamics, but some make approximations of it. Nevertheless, seismic waves are not computed in any of the many‐fault simulators focused on here. The faults are typically approximated by many rectangular elements, although the future use of triangles would allow more accurate representation of curved fault surfaces. This paper briefly describes the features that are common to all of the earthquake simulators discussed in this topical issue of SRL . Following it are four papers (Pollitz, 2012; Richards‐Dinger and Dieterich, 2012; Sachs et al. , 2012; Ward, 2012) authored by each of the groups, which present features of their simulator that go beyond this generic description. Results from using these simulators are not presented in those papers but are contained within a subsequent paper (Tullis et al. , 2012) that compares the results of using these five simulators on an all‐California fault model, allcal2. A detailed description of this fault model can be found at http://scec.usc.edu/research/eqsims/, and the formats used for input and output by our group are described by Barall (2012). ### Fault Geometry and Slip Rates UCERF …