Materials-science aspects on the velocity and temperature dependence of fault strength at high slip velocities

点击翻译按钮获取中文摘要

With increasing temperature, frictional strength of dolerite decreases up to 400 degrees C, then increases up to 800 degrees C, and decreases again up to 1000 degrees C. The frictional strength up to 800 degrees C has a negative correlation with the amount of amorphous phase, while it has a positive correlation with the amount of iron oxides. At 1000 degrees C, granular flow of oxidization reaction products derived from pyroxenes likely reduced the frictional strength.We also conducted friction experiments on dolerite gouges ground for different periods of time at low to high slip velocities. Gouges ground for longer periods of time were stronger at slip velocities slower than 4 cm/s, whereas they were weaker at slip velocities faster than 4 cm/s. We revealed that such difference in frictional strength according to grinding time is attributed to the amount of water adsorbed in amorphous gouge.