统计地震学的两个基本定律对应力的共同依赖
Clément Narteau1, Svetlana Byrdina, Peter Shebalin
1Institut de Physique du Globe de Paris (UMR 7154, CNRS, Univ. P7), 4 Place Jussieu, 75252 Paris Cedex 05, France. narteau@ipgp.jussieu.fr
Nature
|December 4, 2009
概括
统计地震学功率定律,如古登堡-里赫特和奥莫里-乌苏关系,受到压力的影响. 余震衰变率 (c值) 与主要冲击断裂风格有所不同,提供了新的应力场洞察力.
科学领域:
- 地震学 地震学
- 统计地震学 统计地震学
- 地质物理学 地质物理学
背景情况:
- 古登堡 - 里克特关系 (地震频率 - 幅度) 和奥莫里 - 乌苏定律 (余震衰变率) 是基本的统计地震学功率定律.
- 最近的研究将古登堡-里希特 b 值与故障风格和压力联系起来.
- 对于Omori-Utsu定律的参数,特别是c值 (时间延迟),与故障风格相关的理解较少.
研究的目的:
- 为了研究主冲击断裂风格与Omori-Utsu定律的c值之间的关系.
- 确定断层风格是否影响余震衰变的发生,类似于其对地震频率-强度分布的影响.
- 探索使用c和b值作为推断应力场的独立工具.
主要方法:
- 根据其主要冲击的断裂风格分析了余震序列.
- 在不同断层风格 (推力,正常,罢工滑动) 中比较了强度定律余震衰变的开始时间延迟 (c值).
- 与古登堡 - 里希特b值对错误风格的依赖现有知识相关的发现.
主要成果:
- 在余震衰变开始之前的时间延迟 (c值) 在推力主冲击中比正常故障主冲击要短得多.
- 冲击滑动主冲击表现出中间c值.
- 这些对c和b值的故障类型依赖性表明应力状态的共同治理.
结论:
- 无论是古登堡-里希特关系 (b值) 还是奥莫里-乌苏定律 (c值),都明显受到主冲击器的断裂风格的影响,并且,通过延伸,环境应力场.
- c和b值作为独立的,有价值的代理用于推断地球的应力场,否则直接测量是具有挑战性的.
- 这项研究为了解地震易发地区的压力制度提供了新的地震工具.
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