Premium
Numerical simulations on megathrust rupture stabilized under strong dilatancy strengthening in slow slip region
Author(s) -
Liu Yajing
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/grl.50298
Subject(s) - slip (aerodynamics) , geology , dilatant , episodic tremor and slip , subduction , seismology , fault (geology) , geotechnical engineering , tectonics , physics , thermodynamics
Episodic slow slip events (SSEs) typically involve a few millimeters to centimeters of slip over several days to months at depths near or further downdip of megathrust seismogenic zones. Despite its widespread presence in subduction margins, it remains unknown how SSEs interact with the seismogenic zone and affect megathrust ruptures. Here, I construct a 2‐D thrust fault model governed by rate‐state friction to investigate how fault dilatancy influences the amplitude and spatial distribution of‘ coseismic slip, afterslip, and SSEs. Model results illustrate that, under strong dilatancy and high pore pressure around the friction stability transition, coseismic rupture stops at the onset of SSEs. Modeled SSEs have lower velocities, longer recurrence intervals and durations, and larger slip amounts as dilatancy becomes stronger, demonstrating a transition from short‐term to long‐term type of SSE behavior. These results qualitatively explain the range of spatial distributions of SSEs and megathrust ruptures observed or inferred in natural subduction zones. Furthermore, the relative depths of SSEs and megathrust afterslip may serve as an indicator of dilatancy effectiveness.