在实验室地震期间的断层外变形反和应变局部化前体
Gabriel G Meyer1, Carolina Giorgetti1,2, Simon Guérin-Marthe1
1LEMR ENAC, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
概括
断层外变形和应变局部化在地震之前发生. 这项研究将这些现象与地震核形成联系起来,表明它们是可靠的早期预警信号.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 岩石机械学 岩石机械学
背景情况:
- 地震学观察表明,断层外的压力局部化和前震迁移可能会在地震之前发生.
- 将这些前体与地震核形成联系在一起的精确机制仍然不太清楚.
研究的目的:
- 为了研究棒滑核和断层外变形之间的关系.
- 为了确定断层外变形是否影响地震核化过程.
主要方法:
- 进行了最先进的摩擦实验,使用油封闭双轴切割装置.
- 在受控的实验室条件下模拟地震核和滑动事件.
主要成果:
- 在条件不稳定的断层 (a-b < 0) 中,发现了stick-slip核化和断层外变形之间的直接联系.
- 观察到非弹性断层变形减少了周围岩石的刚性,促进了地震核形成.
- 在实验室实验中观察到,在stick-slip周期期间,在断层周围的先决应变局部化.
结论:
- 卷度变形过程可能是大地震核形成的关键因素.
- 观察到的菌株局部化可以作为即将发生的大型地震的可靠指标.
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