在帕克菲尔德的圣安德烈亚斯断层内部,通过垂直地震分析进行了观察
J Andres Chavarria1, Peter Malin, Rufus D Catchings
1Division of Earth and Ocean Sciences, Nicholas School of Environment and Earth Sciences, Duke University, Box 90227, Durham, NC 27708, USA. jac4@duke.edu
Science (New York, N.Y.)
|December 6, 2003
概括
来自圣安德烈亚斯断层观测站的地震数据显示分散的波浪,表明主要断层和次要断层. 这些发现表明了显著的物质性能对比,可能是由于裂或流体.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 结构地质学 结构地质学
背景情况:
- 圣安德烈亚斯断层深度观测站 (SAFOD) 试验孔位于帕克菲尔德圣安德烈亚斯断层的西南侧.
- 该天文台配备了一个垂直地震分析 (VSP) 阵列,用于调查地下结构.
研究的目的:
- 分析微型地震的VSP地震图,以确定地下断层结构.
- 为了研究P波和S波之间的地震信号的性质.
主要方法:
- 使用垂直地震分析 (VSP) 阵列记录微型地震的地震图.
- 分析地震波散射模式及其起源.
主要成果:
- 在VSP地震图中观察到P波和S波之间的异常信号.
- 确定了地震散射点的平面表面,解释为圣安德烈亚斯断层和四个次要断层.
- 根据P-S波转换的强度推断出材料特性中的显著对比.
结论:
- 散射模式证实了圣安德烈亚斯断层和相关的次要断层的存在和几何.
- 观察到的波浪转换表明,断层区域内存在裂或流体,表明岩石特性存在重大变化.
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