Cascading rupture of a megathrust.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35507667.
- Also identified by DOI 10.1126/sciadv.abm4131 and PMC identifier 9067933.
- Licence recorded as CC BY-NC.
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Abstract
Understanding variability in the size and location of large earthquakes along subduction margins is crucial for evaluating seismic and tsunami hazards. We present a coseismic slip model for the 2021 <i>M</i>8.2 Chignik earthquake and investigate the relationship of this earthquake to previous major events in the Alaska Peninsula region and to interseismic coupling. Stress changes from the 2020 <i>M</i>7.8 Simeonof event triggered the Chignik event, and together, the earthquakes partially filled an unruptured section along a 3000-km subduction margin that has experienced a series of ruptures along almost its entire length over the past century. Variations in coupling and structural characteristics may make the region more prone to nucleating <i>M</i>7 to <i>M</i>8 events rather than larger <i>M</i> > 8.5 earthquakes. Stress changes and rupture areas suggest that the two recent earthquakes may be part of an 80-year-long rupture cascade and may have advanced seismic hazard in the region.