Intraplate seismicity, hydroseismicity, and predictions in hindsight
Intraplate seismicity, hydroseismicity, and predictions in hindsight
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DOI：
10.1785/gssrl.79.4.578
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发表时间：
2008-07-01
影响因子：
3.3
通讯作者：
Costain, John K.
中科院分区：
文献类型：
--
作者：
Costain, John K.
板内地震的特征是空间上孤立的持续、扩散的地震活动区域，与已测绘的地表地质没有普遍的相关性。关于它们的起源，人们提出了各种各样的模型，但没有一个被广泛接受的解释。在这里，我展示了地表流量属性（年平均流量，流量标准偏差）与弗吉尼亚州、西弗吉尼亚州和密苏里州新马德里的震中地理分布之间的空间相关性，支持了降雨在板内地震产生中起关键作用的假设。地球-大气界面（地下水位、水库-地表、河段）高度的波动与孔隙流体压力瞬变有关，这种压力瞬变传递到震源深处，从而引发地震。这种由气象学和地形学驱动的模式被称为“水文地震活动性”。新的结果将主要河流的流量与震中的分布联系起来，并揭示了地球表面水的供应与地震震中的面积分布之间的明确相关性。此外，在弗吉尼亚州和西弗吉尼亚州发生的三次大型板内地震的时间与飓风卡米尔和阿格尼斯有关，加上已知或推断的地壳水力扩散系数值，表明气象脉冲与地震之间存在因果关系。
Intraplate earthquakes are characterized by spatially isolated regions of persistent, diffuse earthquake activity with no general correlation with mapped surface geology. Various models have been proposed for their origin, but there has been no widely accepted explanation. Here I show a spatial correlation between surface streamflow attributes (mean annual streamflow, standard deviation of streamflow) and the geographic distribution of epicenters in Virginia, West Virginia, and New Madrid, Missouri, supporting the hypothesis that rainfall plays a key role in the generation of intraplate earthquakes. Fluctuations in the elevation of the earth-atmosphere interface (water table, reservoir-surface, river stage) are associated with pore-fluid pressure transients that are transmitted to hypocentral depths where they trigger earthquakes. Such a meteorologically and topographically driven model has been referred to as "hydro-seismicity." The new results link flow in major rivers to the distribution of epicenters and reveal a clear correlation between the supply of water at the Earth's surface and the areal distribution of earthquake epicenters. In addition, the timing of three large intraplate earthquakes in Virginia and West Virginia with respect to hurricanes Camille and Agnes, together with the known or inferred values of crustal hydraulic diffusivity, suggests a causal relationship between the meteorologic impulses and the earthquakes.