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Slip‐pulse rupture behavior on a 2 m granite fault
Author(s) -
McLaskey Gregory C.,
Kilgore Brian D.,
Beeler Nicholas M.
Publication year - 2015
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 - 10.1002/2015gl065207
Subject(s) - slipping , seismology , geology , slip (aerodynamics) , shear (geology) , wave speed , episodic tremor and slip , seismic wave , fault (geology) , subduction , mechanics , tectonics , physics , petrology , structural engineering , engineering , thermodynamics
We describe observations of dynamic rupture events that spontaneously arise on meter‐scale laboratory earthquake experiments. While low‐frequency slip of the granite sample occurs in a relatively uniform and crack‐like manner, instruments capable of detecting high‐frequency motions show that some parts of the fault slip abruptly (velocity > 100 mm s −1 , acceleration > 20 km s −2 ) while the majority of the fault slips more slowly. Abruptly slipping regions propagate along the fault at nearly the shear wave speed. We propose that the dramatic reduction in frictional strength implied by this pulse‐like rupture behavior has a common mechanism to the weakening reported in high‐velocity friction experiments performed on rotary machines. The slip pulses can also be identified as migrating sources of high‐frequency seismic waves. As observations from large earthquakes show similar propagating high‐frequency sources, the pulses described here may have relevance to the mechanics of larger earthquakes.