深层流体,和沿着圣安德烈亚斯断层中心的爬行之间的相关性
Michael Becken1, Oliver Ritter, Paul A Bedrosian
1GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany. michael.becken@uni-muenster.de
Nature
|December 2, 2011
概括
深层流体迁移到圣安德烈亚斯断层,影响地震活动和断层强度. 这种来自地幔的流体流入解释了帕克菲尔德和科拉梅附近的震动和断层弱点的变化.
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:
- 圣安德烈亚斯断层在短距离上表现出明显的地震性模式.
- 断层弱点归因于诸如弱矿物质,高流体压力和化学弱化等因素.
- 非火山性震与深层毛孔流体压力有关.
研究的目的:
- 为了研究圣安德烈亚斯断层系统内的流体迁移.
- 为了将液体存在与震动活动和断裂强度变化相关联.
- 了解深层流体在断层减弱中的作用.
主要方法:
- 磁铁度 (MT) 数据成像电阻.
- 地物理证据分析. 地物理证据分析.
- 地震震动与地质结构的相关性.
主要成果:
- 地质数据显示,流体从上层地幔迁移到圣安德烈亚斯断层.
- 震的沿冲击变化与地的下层和上层地幔的强度相关.
- 低电阻区域表明相互连接的流体,特别是在帕克菲尔德 - 乔拉姆的西南.
- 在Cholame附近的液体积累被困在一个高电阻度的盖子下面,集中震.
- 在SAFOD附近的垂直低电阻区域表明深流体通道进入东部断层块.
结论:
- 深层流体流入圣安德烈亚斯断层系统得到证实.
- 来自地幔的流体会影响震动和断层强度.
- 流体迁移路径和捕获机制解释了局部的地震和机械行为.
- 这支持了流体诱导的断层减弱的假设,通过高孔隙压力在脆脆的地.
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