Secondary acceleration of slip fronts driven by slow slip event coalescence in subduction zones.

ABSTRACT: The coalescence of slow slip events (SSEs) in subduction zones has been proposed as a potential precursor to large earthquakes, yet the physical conditions under which SSE fronts coalesce remain poorly understood. Here, we investigate coalescing SSEs along the Cascadia subduction zone. Using Global Navigation Satellite System (GNSS) data, we invert for the spatiotemporal evolution of the slip rate of SSEs from 2012 to 2023. We identify a coalescing event in 2021, which occurred during a phase of SSEs moment rate decrease, contrary to the previously documented 2013 coalescence. Coalescence triggered a secondary increase in slip rate and a rupture expansion in the 2021 event. To explore the mechanisms driving coalescence, we perform numerical simulations based on rate-and-state friction. Our

SUBMITTER: Wang J 

PROVIDER: S-EPMC12572340 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature