由于粘弹性应力转移而延迟触发了1999年赫克托矿山地震
1Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington DC 20015, USA. freed@dtm.ciw.edu
Nature
|May 11, 2001
概括
地震压力转移可以引发新的地震. 登陆者和赫克托矿山地震之间的7年延迟是由下层地的流动解释的,这增加了赫克托矿山断层的压力.
科学领域:
- * 地震学和构造物理学
- *地震力学和断层相互作用
背景情况:
- *地震可以改变附近断层的压力,可能引发随后的地震事件.
- * 1999年的赫克托矿地震是在1992年的兰德斯地震之后7年发生的,这表明存在潜在的因果关系.
- *先前对Landers地震所产生的共震应力变化的分析,对应力转移到Hector Mine的低中心产生了模两可的结果.
研究的目的:
- * 调查粘弹性应力转移在Landers和Hector矿山地震之间的7年延迟中的作用.
- * 模拟大地震后地球地和地幔的应力演变.
主要方法:
- * 开发和应用一个三维粘弹性模型.
- *模拟应力从柔性下层和上层地幔转移到脆弱的上层.
- *使用在Landers地震后观察到的水平表面变形对模型进行校准.
主要成果:
- *粘弹性建模表明,在赫克托矿的低中心位置,地震后应力显著增加 (1-2 bar).
- * 低地或上地流被确定为驱动这7年压力增加的机制.
- * 模拟的应力变化为延迟发生的赫克托矿山地震提供了合理的解释.
结论:
- *粘弹性过程在大地震后的长期压力积累和转移中起着至关重要的作用.
- *地震后应力变化,由性流动驱动,对于理解地震触发和序列至关重要.
- *将粘弹性纳入地震危险评估对于准确地预测地震至关重要.
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