通过脱水蛇形模拟俯冲区的地震性
David P Dobson1, Philip G Meredith, Stephen A Boon
1Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany. d.dobson@ucl.ac.uk
概括
抗原石蛇形岩中的脱水反应会产生地震信号. 这些发现表明,脱水导致的流体压力可以在压下构造板块的中间深度引起地震.
科学领域:
- 地质物理学 地质物理学
- 矿物物理 矿物物理
- 地震学 地震学
背景情况:
- 抗戈里特蛇形岩是起构造板块的关键组成部分.
- 在高压和高温下,蛇形岩内部的脱水反应尚不清楚.
- 在中间深度 (50-200公里) 产生地震性仍然是地球科学中的一个重要问题.
研究的目的:
- 在实验室条件下研究抗戈脱水的地震后果.
- 为了将脱水反应与脆性变形和流体压力产生联系起来.
- 为了提供一个机制,在潜伏区中介深度的地震性.
主要方法:
- 实验使用多压机进行,以模拟潜水带条件.
- 在1.58.5GPa的压力范围和300900°C的温度范围内,在抗戈里特脱水过程中测量了声辐射能量.
- 回收的样本被分析了微观结构和变形特征.
主要成果:
- 在抗戈里特脱水过程中,声辐射信号被强烈检测到.
- 对实验样品的分析揭示了脆弱的变形结构.
- 这些结构与孔液压的升高有关,这表明脱水期间会释放液体.
结论:
- 在模拟的降温条件下,抗戈里特的脱水会产生显著的声学信号.
- 相关的脆性变形和高孔流体压力为地震产生提供了一个合理的机制.
- 沉积板中的脱水反应是中等深度地震的可行来源.
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