Metrics for Comparing Dynamic Earthquake Rupture Simulations

Abstract

Online Material: Explanation of the concept of a dynamic rupture simulation. Earthquakes are complex events that involve a myriad of interactions among multiple geologic features and processes. One of the tools that is available to assist with their study is computer simulation, particularly dynamic rupture simulation. A dynamic rupture simulation is a numerical model of the physical processes that occur during an earthquake. Starting with the fault geometry, friction constitutive law, initial stress conditions, and assumptions about the condition and response of the near‐fault rocks, a dynamic earthquake rupture simulation calculates the evolution of fault slip and stress over time as part of the elastodynamic numerical solution (![Graphic][1] see the simulation description in the electronic supplement to this article). The complexity of the computations in a dynamic rupture simulation make it challenging to verify that the computer code is operating as intended, because there are no exact analytic solutions against which these codes’ results can be directly compared. One approach for checking if dynamic rupture computer codes are working satisfactorily is to compare each code’s results with the results of other dynamic rupture codes running the same earthquake simulation benchmark. To perform such a comparison consistently, it is necessary to have quantitative metrics. In this paper, we present a new method for quantitatively comparing the results of dynamic earthquake rupture computer simulation codes. Over the past decade, the Southern California Earthquake Center–U.S. Geological Survey (SCEC‐USGS) Spontaneous Rupture Code Verification Project has published a series of computational dynamic rupture benchmark exercises (Harris and Archuleta, 2004; Harris et al. , 2009, 2011). The benchmarks, a subset of which of are shown in Figure 1, are listed on the project’s website (http://scecdata.usc.edu/cvws, last accessed November 2014) and cover many earthquake settings, including a range of fault geometries (strike‐slip faults, normal faults, … [1]: /embed/inline-graphic-1.gif