Electric potential changes associated with nucleation of stick-slip of simulated gouges
Electric potential changes associated with nucleation of stick-slip of simulated gouges
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DOI：
10.1016/j.tecto.2011.01.018
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发表时间：
2011-04
期刊：
影响因子：
2.9
通讯作者：
Kumi Onuma;J. Muto;H. Nagahama;K. Otsuki
中科院分区：
文献类型：
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作者：
Kumi Onuma;J. Muto;H. Nagahama;K. Otsuki
我们的摩擦实验，使用模拟的断层检测到先兆的电位变化之前粘滑事件。在压电石英和非压电辉长岩泥中都检测到了这些前兆电信号。电位的变化是由非常靠近与粘滑事件之前的缓慢滑动相关联的断层面的电极组局部检测的。与应力逐步释放有关的断层滑动量与起电量成正比，说明起电是一个与滑动有关的过程。根据对代表性样品的详细微观结构分析，已知在稳定滑动期间形成的Riedel（R1）剪切是在检测瞬时电压变化的电极对周围最密集地发展的。这表明，局部电压的增加可能是由于摩擦带电，由于缓慢滑动的R1剪切在成核阶段的粘滑事件。我们的实验结果表明，天然断层较厚的断层泥区将需要更大的地震滑动，导致更大的电信号在地震的成核阶段。
Our friction experiments using simulated gouges detected premonitory changes in electric potential before stick-slip events. These precursor electric signals have been detected both in piezoelectric quartz and non-piezoelectric gabbroic gouges. The changes in the potential were locally detected by electrodes set very close to the fault surface associated with slow slip prior to stick-slip events. The magnitude of electrification is proportional to fault slip associated with gradual stress releases, indicating that the electrification is slip-dependent process. From the detailed microstructural analyses on a representative sample, Riedel (R1) shears known to be formed during stable sliding were the most densely developed around the electrode pair which detected the precursory voltage changes. This indicates that local increases in the voltages were likely caused by frictional electrification due to slow slip on R1shears in nucleation phases of stick-slip events. Our experimental results imply that natural faults with thicker gouge zones would require greater precursory slips, resulting in larger electric signals in the nucleation phase of earthquakes.