5. Influence of Subducting Topography on Earthquake Rupture

Abstract

Rupture models for large subduction zone earthquakes suggest significant heterogeneity in slip and moment release over the fault plane. Attempts to characterize the nature of the high-slip regions led to descriptions of these earthquakes in the context of the asperity model and allowed for subduction zones to be classified on the basis of likely earthquake asperity distributions. Understanding the physical features in the fault zone that produce these highslip regions is still a challenge. Detailed bathymetric and seismic data collection in several subduction zones has led to correlations between large earthquake rupture patterns and subducting features such as seamounts and ridges. This is not a simple relationship, and it is not consistent in all subduction zones. Earthquakes at several subduction zones appear to concentrate slip on subducted features, but others have features that act as barriers to earthquake rupture. Additional questions remain about the temporal stability of high-slip regions. More research is needed to understand the connections between the upper plate, fault friction, subducting features, and overall subduction zone stresses and the patterns of large earthquakes in this complex environment.