Abstract
Changes in the frequency of intermediate-depth (60–300 km) earthquakes in response to static stress transfer can provide insights into the mechanisms of earthquake generation within subducting slabs. In this study, we use the most up-to-date global and regional earthquake catalogs to show that both the aftershock productivity of large earthquakes, and the changes in the frequency of intermediate-depth earthquakes around the timing of major megathrust slip, support the view that faults within the slab are relatively insensitive to static stress transfer on the order of earthquake stress drops. We interpret these results to suggest the population of faults within the slab are much further from their failure stress than is typical for shallow fault systems. We also find that aftershock productivity varies within slabs over small spatial scales, indicating that the mechanism that enables faults to rupture at intermediate depths is likely to be spatially heterogeneous over length-scales of a few tens of kilometres. We suggest dehydration-related weakening mechanisms can best account for this heterogeneity.
| Original language | English |
|---|---|
| Article number | e2022JB026269 |
| Journal | Journal of Geophysical Research: Solid Earth |
| Volume | 128 |
| Issue number | 6 |
| Early online date | 12 Jun 2023 |
| DOIs | |
| Publication status | Published - 14 Jun 2023 |
Bibliographical note
Funding Information:The authors were supported in this work by the Royal Society under URF\R1\180088 and RF\ERE\210041. SW and TJC were also supported through COMET, the UK Natural Environment Research Council's Centre for the Observation and Modelling of Earthquakes, Volcanoes, and Tectonics. We thank Jorge Jara for useful discussions about his work on northern Chile. We also thank the Editor, Associate Editor, and two anonymous reviews for their helpful comments on the manuscript.
Publisher Copyright:
© 2023. The Authors.