Physical and Statistical Behavior of Multifault Earthquakes: Darfield Earthquake Case Study, New Zealand

Abstract

We use Coulomb stress change (CSC) analyses and seismicity data to model the physical and statistical behavior of the multifault source of the 4 September 2010 Mw 7.1 Darfield earthquake in New Zealand. Geodetic and seismologic data indicate this earthquake initiated on a severely misoriented reverse fault and propagated across a structurally complex fault network including optimally oriented faults. The observed rupture sequence is most successfully modeled if maximum CSC imposed by rupture of the hypocentral fault on to receiver faults exceeds theoretical threshold values of 1 to 5 MPa that are assigned based on fault slip tendency and stress drop analyses. CSC modeling using the same crit..