2009年萨摩亚 - 加大地震引发了双重地震
Thorne Lay1, Charles J Ammon, Hiroo Kanamori
1Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, California 95064, USA. tlay@ucsc.edu
Nature
|August 21, 2010
概括
一个罕见的2009年加地震序列看到一个不寻常的板内部事件引发了巨大的板间断层,显著增加了地震和海的危险. 这种复杂的断裂造成了毁灭性的海波和广泛的余震.
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:
- 大地震通常涉及板间断裂,这可能会引发附近的板内余震.
- 通常的模式是板间事件激活板内地震性,而不是相反.
研究的目的:
- 为了分析一个罕见的地震序列在加的俯冲区,其中一个内部板块地震引发了板块间断层.
- 了解与这种反向断裂模式相关的地震和海危险.
主要方法:
- 对地震波数据的分析,以区分不同的断层断裂.
- 调查2009年9月29日加地震的序列,包括其时刻大小和断裂机制.
主要成果:
- 一次8.1级的板内地震在几分钟内触发了两个主要的板内地震 (每次7.8级) 的次事件.
- 合并的断层产生了高达12米的海波,造成萨摩亚,美属萨摩亚和加的死亡.
- 详细的地震分析揭示了具有不同几何形状的明显断层,包括触发推力断层.
结论:
- 2009年加地震序列显示,典型的地震触发模式发生了逆转.
- 这一事件显著扩大了地震和海的危险性,突出了板间和板内断层之间的复杂相互作用.
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