Dynamic stresses, Coulomb failure, and remote triggering

Bulletin of the Seismological Society of America
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Abstract

Dynamic stresses associated with crustal surface waves with 15-30-sec periods and peak amplitudes < 1 MPa are capable of triggering seismicity at sites remote from the generating mainshock under appropriate conditions. Coulomb failure models based on a frictional strength threshold offer one explanation for instances of rapid-onset triggered seismicity that develop during the surface-wave peak dynamic stressing. Evaluation of the triggering potential of surface-wave dynamic stresses acting on critically stressed faults using a Mohr's circle representation together with the Coulomb failure criteria indicates that Love waves should have a higher triggering potential than Rayleigh waves when incident on vertical, strike-slip faults. That (1) the onset of triggered seismicity often appears to begin during the Rayleigh wave rather than the earher-arriving Love wave, (2) vertical strike-slip faults pervade the crust in most tectonic regimes, and (3) Love-wave amplitudes typically exceed those for Rayleigh waves suggests that the explanation for rapid-onset dynamic triggering may not reside solely with a simple static-threshold friction mode. The results also indicate that thrust faults should be more susceptible to dynamic triggering by Rayleigh-wave stresses than normal faults in the shallow seismogenic crust (< 5 km), while the reverse should be true in the lower seismogenic crust (> 5 km). The latter is consistent with the observation that extensional or transtensional tectonic regimes are more susceptible to remote triggering by Rayleigh-wave dynamic stresses than compressional or transpressional regimes. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Dynamic stresses, Coulomb failure, and remote triggering
Series title Bulletin of the Seismological Society of America
DOI 10.1785/0120070049
Volume 98
Issue 1
Year Published 2008
Language English
Contributing office(s) Volcano Hazards Program
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Bulletin of the Seismological Society of America
First page 66
Last page 92