Sensitivity of the Static Earthquake Triggering Mechanism to Elastic Heterogeneity and Main Event Slip

This paper has evolved out of our previous work on static stress trans-fer, where we used the full-space elastostatic Green’s tensor to compute the Coulomb stress transfer impact of the Landers earthquake on the Hec-tor Mine event. In this work, we use the elastostatic Green’s tensor for an arbitrary layered Earth model with free-surface boundary conditions to study the impact of elastic heterogeneity as well as source-fault slip and geometry on the stress transfer mechanism. Slip distribution and fault geometry of the source have a significant impact on the stress transfer, especially in case of spatially extended triggered events. Maximization of the Coulomb stress transfer function for known aftershocks provides a mechanism for inverting for the source event slip. Heterogeneity of the elastic earth parameters is shown to have a sizeable, but lower-magnitude, impact on the static stress transfer in 3D. The analysis is applied to Lan-ders/Hector Mine and 100 small “aftershocks ” of the Landers event. A computational toolkit is provided for the study of static stress transfer for arbitrary source and receiver faults in layered Earth.