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.

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