Re-Examining Temporal Variations in Intermediate-Depth Seismicity

A well-established characteristic of intermediate-depth earthquakes is that they are deficient in aftershocks to shallow earthquakes of equivalent magnitude. The lack of aftershocks suggests faults within slabs are relatively insensitive to static stress changes on the order of earthquake stress drops. In contrast, some studies have reported significant changes in the frequency of seismicity within slabs following Mw 8-9 megathrust earthquakes, which would imply some level of stress sensitivity to stress transfer at intermediate depths. I will describe work searching for globally consistent signals of earthquake rate-changes within subducting slabs in response to stress transfer using both regional and global earthquake catalogues and outline some implications of our findings for the mechanisms of intermediate-depth earthquake generation.