Earthquake recurrence in simulated fault systems

James H. Dieterich, & Keith B. Richards-Dinger

Under Review 2009, SCEC Contribution #1273

We employ a computationally efficient fault system earthquake simulator, RSQSim, to explore effects of earthquake nucleation and fault system geometry on earthquake occurrence. The simulations incorporate rate- and state-dependent friction, high-resolution representations of fault systems, and quasi-dynamic rupture propagation. Faults are represented as continuous planar surfaces, surfaces with a random fractal roughness, and discontinuous fractally segmented faults. Simulated earthquake catalogs have up to $10^6$ earthquakes that span a magnitude range from $\sim.5 to M8. The seismicity has strong temporal and spatial clustering in the form of foreshocks and aftershocks and occasional large-earthquake pairs. Fault system geometry plays the primary role in establishing the characteristics of stress evolution that control earthquake recurrence statistics. Empirical density distributions of earthquake recurrence times at a specific point on a fault depend strongly on magnitude and take a variety complex forms that change with position within the fault system. Because fault system geometry is an observable that has a great impact on recurrence statistics, we propose using fault system earthquake simulators to define the empirical probability density distributions for use in regional assessments of earthquake probabilities.

Citation
Dieterich, J. H., & Richards-Dinger, K. B. (2009). Earthquake recurrence in simulated fault systems. Pure And Applied Geophysics, (under review).