Open AccessShear and normal load perturbations on a two‐dimensional continuous fault: 2. Dynamic triggering
Author(s) -
Perfettini H.,
Schmittbuhl J.,
Cochard A.
Publication year - 2003
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jb001805
Subject(s) - amplitude , instability , geology , slip (aerodynamics) , shear (geology) , nucleation , fault (geology) , mechanics , seismology , physics , thermodynamics , quantum mechanics , petrology
We study the consequences of temporal stress perturbations on earthquake nucleation in a continuous fault model. Using a two‐dimensional (2‐D) quasi‐dynamic model of a strike‐slip fault governed by a rate‐and‐state friction law with depth variable properties, we show that dynamic triggering (due to stress pulses or wave packets), although allowed by our results, is an exception rather than a rule and should be limited to understressed areas such as areas of high pore pressures or to faults at the very end of their earthquake cycle. When periodic stress perturbations are sensitive, the response of the fault is frequency‐independent for periods lower than a period T 0 but strongly depends on the frequency for periods larger than T 0 . We demonstrate that the crossover period T 0 is equal to the time left until the earthquake instability. According to our model, high frequencies are demonstrated to have a higher triggering potential than low ones, which makes tidal triggering very unlikely before the end of the cycle due to the very low amplitudes of the stress perturbations involved.