Discrete Element Modeling of a Subduction Zone with a Seafloor Irregularity and its Impact on the Seismic Cycle

Liqing Jiao, Chung Han Chan, Luc Scholtès, Aurélia Hubert-Ferrari, Frédéric Victor Donzé, Paul Tapponnier

Research output: Contribution to journalArticlepeer-review

Abstract

Seafloor irregularities influence rupture behavior along the subducting slab and in the overriding plate, thus affecting earthquake cycles. Whether seafloor irregularities increase the likelihood of large earthquakes in a subduction zone remains contested, partially due to focus put either on fault development or on rupture pattern. Here, we simulate a subducting slab with a seafloor irregularity and the resulting deformation pattern of the overriding plate using the discrete element method. Our simulations illustrate the rupture along three major fault systems: megathrust, splay and backthrust faults. Our results show different rupture dimensions of earthquake events varying from tens to ca. 140 km. Our results suggest that the recurrence interval of megathrust events with rupture length of ca. 100 km is ca. 140 years, which is overall comparable to the paleoseismic records at the Mentawai area of the Sumatran zone. We further propose the coseismic slip amounts decrease and interseismic slip amounts increase from the surface downwards gradually. We conclude that the presence of seafloor irregularities significantly affects rupture events along the slab as well as fault patterns in the overriding plate.

Original languageEnglish
Pages (from-to)776-790
Number of pages15
JournalActa Geologica Sinica
Volume96
Issue number3
DOIs
StatePublished - Jun 2022

Keywords

  • Mentawai
  • backthrust faults
  • discrete element modeling
  • megathrust
  • seamount
  • splay
  • subduction zone

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