Ultralow friction of carbonate faults caused by thermal decomposition.
High-velocity weakening of faults may drive fault motion during large earthquakes. Experiments on simulated faults in Carrara marble at slip rates up to 1.3 meters per second demonstrate that thermal decomposition of calcite due to frictional heating induces pronounced fault weakening with steady-state friction coefficients as low as 0.06. Decomposition produces particles of tens of nanometers in size, and the ultralow friction appears to be associated with the flash heating on an ultrafine decomposition product. Thus, thermal decomposition may be an important process for the dynamic weakening of faults.
Han
Raehee
R
Department of Earth and Environmental Sciences, Korea University, Seoul 136-701, South Korea. rhhan@korea.ac.kr
Shimamoto
Toshihiko
T
Hirose
Takehiro
T
Ree
Jin-Han
JH
Ando
Jun-Ichi
J