Modeling the seismic cycle in subduction zones: The role and spatiotemporal occurrence of off-megathrust earthquakes
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Date
2014-02-28
Publication Type
Journal Article
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yes
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Abstract
Shallow off-megathrust subduction events are important in terms of hazard assessment and coseismic energy budget. Their role and spatiotemporal occurrence, however, remain poorly understood. We simulate their spontaneous activation and propagation using a newly developed 2-D, physically consistent, continuum, viscoelastoplastic seismo-thermo-mechanical modeling approach. The characteristics of simulated normal events within the outer rise and splay and normal antithetic events within the wedge resemble seismic and seismological observations in terms of location, geometry, and timing. Their occurrence agrees reasonably well with both long-term analytical predictions based on dynamic Coulomb wedge theory and short-term quasi-static stress changes resulting from the typically triggering megathrust event. The impact of off-megathrust faulting on the megathrust cycle is distinct, as more both shallower and slower megathrust events arise due to occasional off-megathrust triggering and increased updip locking. This also enhances tsunami hazards, which are amplified due to the steeply dipping fault planes of especially outer rise events.
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Publication status
published
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Book title
Journal / series
Volume
41 (4)
Pages / Article No.
1194 - 1201
Publisher
American Geophysical Union
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Software
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Date collected
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Subject
Seismic cycle; Off-megathrust seismicity; Dynamic Coulomb wedge theory; Subduction zone; Seismo-thermo-mechanical modeling; Tsunami
Organisational unit
03698 - Tackley, Paul / Tackley, Paul
03971 - Fichtner, Andreas / Fichtner, Andreas