在实验室实验中确定的东北-奥基巨型冲击中低震剪压力
Kohtaro Ujiie1, Hanae Tanaka, Tsubasa Saito
1Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.
概括
2011年东北奥基地震显示了较大的浅滑,此前认为不太可能. 实验揭示了丰富的粘土和热压缩解释了这种巨大的断层运动和随后的海.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 构造学 构造学 构造学 构造学
背景情况:
- 浅板边界推力预计不会产生大规模的地震滑动.
- 2011年东北奥基地震 (Mw = 9.0) 在日本沟附近产生了50米的流离失所,造成了毁灭性的海.
研究的目的:
- 调查在东北大震期间观察到的异常大的断层运动背后的机制.
- 确定导致板边推力显著浅滑的因素.
主要方法:
- 进行了高速 (1.3 m/s) 摩擦实验.
- 使用的岩石样本从负责东北奥基地震的板块边界推力中获取.
主要成果:
- 在摩擦实验中观察到微小的应力下降.
- 测量了非常低的峰值和稳定状态切削应力.
- 确定了大量的弱粘土 (smectite) 和热压缩效应.
结论:
- 丰富的斯麦克提特粘土和热压缩使断层滑动更加容易.
- 这些因素解释了2011年东北奥基地震期间的大浅滑坡.
- 在浅的推力断层上提供了巨大的位移机制.
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