A Global Set of Subduction Zone Earthquake Scenarios and Recurrence Intervals Inferred From Geodetically Constrained Block Models of Interseismic Coupling Distributions

Abstract

Abstract The past 100 years have seen the occurrence of five MW≥9 earthquakes and 94 MW≥8 earthquakes. Here we assess the potential for future great earthquakes using inferences of interseismic subduction zone coupling from a global block model incorporating both tectonic plate motions and earthquake cycle effects. Interseismic earthquake cycle effects are represented using a first‐order quasistatic elastic approximation and include ∼107km2 of interacting fault system area across the globe. We use estimated spatial variations in decadal‐duration coupling at 15 subduction zones and the Himalayan range front to estimate the locations and magnitudes of potential seismic events using empirical scaling relationships relating coupled area to moment magnitude. As threshold coupling values increase, estimates of potential earthquake magnitudes decrease, but the total number of large earthquakes varies non‐monotonically. These rupture scenarios include as many as 14 recent or potential MW≥9 earthquakes globally and up to 18 distinct MW≥7 events associated with a single subduction zone (South America). We also combine estimated slip deficit rates and potential event magnitudes to calculate recurrence intervals for large earthquake scenarios, finding that almost all potential earthquakes would have a recurrence time of less than 1,000 years.