کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6428174 | 1634727 | 2015 | 10 صفحه PDF | دانلود رایگان |
- High velocity friction experiments on cohesive rocks under undrained conditions.
- Experimental evidence of thermo-mechanical pressurization (TMP).
- TMP weakening of cohesive rocks is negligible during earthquakes.
Earthquakes occur because fault friction weakens with increasing slip and slip rates. Since the slipping zones of faults are often fluid-saturated, thermo-mechanical pressurization of pore fluids has been invoked as a mechanism responsible for frictional dynamic weakening, but experimental evidence is lacking. We performed friction experiments (normal stress 25 MPa, maximal slip-rate â¼3 msâ1) on cohesive basalt and marble under (1) room-humidity and (2) immersed in liquid water (drained and undrained) conditions. In both rock types and independently of the presence of fluids, up to 80% of frictional weakening was measured in the first 5 cm of slip. Modest pressurization-related weakening appears only at later stages of slip. Thermo-mechanical pressurization weakening of cohesive rocks can be negligible during earthquakes due to the triggering of more efficient fault lubrication mechanisms (flash heating, frictional melting, etc.).
Journal: Earth and Planetary Science Letters - Volume 429, 1 November 2015, Pages 1-10