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Moisture‐related weakening and strengthening of a fault activated at seismic slip rates
Author(s) -
Mizoguchi Kazuo,
Hirose Takehiro,
Shimamoto Toshihiko,
Fukuyama Eiichi
Publication year - 2006
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 - 10.1029/2006gl026980
Subject(s) - moisture , slip (aerodynamics) , drop (telecommunication) , fault gouge , humidity , geotechnical engineering , geology , fault (geology) , water content , materials science , seismology , composite material , meteorology , thermodynamics , telecommunications , physics , computer science
From high‐velocity friction experiments on gabbro rock at a rate of 85 mm/s, we found that a fault with a thin gouge layer experienced slip weakening with a drop of about 80% in the friction coefficient. At room humidity conditions, the fault subsequently recovered its complete strength, over an interval of several minutes after the slip terminated. The strength recovery did not occur under dry N 2 gas‐saturated condition. This result can be interpreted as the interaction of moisture with gouge particles: moisture‐drained weakening due to frictional heating and moisture‐absorbed strengthening due to cooling. This new mechanism can cause dynamic weakening of faults, which controls earthquake rupture propagation.