An Objective Method for Estimating Earthquake Rupture Dimensions From Early Aftershock Distributions Across a Wide Magnitude Range

Date: 4/25/2019

Time: 09:00 AM

Room: Cascade I

Aftershock distributions are commonly used to constrain some of the most fundamental macroscopic properties of seismic ruptures, such as rupture source dimensions. Although any individual aftershock sequence may exhibit complicated aftershock patterns, there are well-defined average patterns of aftershock behavior in space, time, and with respect to magnitude. Here we propose a simple new method for characterizing seismicity sequences in a data-driven way. The method is based on an eigenvalue decomposition of earthquake hypocenter clusters and provides an objective characterization of the evolution of event sequences in space and time. We apply the method to relocated seismicity catalogs from California and Japan. Our preliminary tests show that the method is able to provide consistent cluster descriptions from the largest observed earthquakes down to relatively small magnitude events (with rupture dimensions on the order of location uncertainties). We use the cluster descriptions i) to develop source dimension scaling relations that are consistent across a very wide magnitude range, and ii) to test a series of earthquake triggering hypotheses regarding on- and off-fault aftershock triggering and aftershock deficits in the primary rupture areas.

Presenting Author: Men-Andrin Meier

Authors