Discrete element modeling of a subduction zone with a seafloor irregularity and its impact on the seismic cycle
Abstract
Seafloor irregularities such as seamounts, ridges, or basins 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 a narrow focus either on fault network development or on rupture pattern. Here, using the discrete element method (DEM), we simulate a subducting slab with a seafloor irregularity and the resulting deformation pattern of the overriding plate, which comprises the fault network development and the associated rupture pattern. Our results show the rupture along three main regions: megathrust, splay and backtrust fault regions and the rupture length various from tens to more than one hundred kilometers. The ruptures distribute along the slab and faults in the overriding plate, since the irregularity could accumulate the stress. The modeled recurrence interval of large events and the lengths of the ruptures are overall comparable to that from the paleoseismic record. Our results show the coseismic slip decreases and interseismic slip increases from the surface downwards. We conclude that the presence of seafloor irregularities significantly affect rupture events along the slab and fault patterns in the overriding plate. Our results thus contribute to seismic and tsunami hazard assessments in subduction zones.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.T13G0312J
- Keywords:
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- 1242 Seismic cycle related deformations;
- GEODESY AND GRAVITYDE: 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGYDE: 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICSDE: 8164 Stresses: crust and lithosphere;
- TECTONOPHYSICS