Earthquake slip weakening and asperities explained by thermal pressurization
Earthquake slip weakening and asperities explained by thermal pressurization
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DOI：
10.1038/nature03901
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发表时间：
2005-08
期刊：
影响因子：
64.8
通讯作者：
C. Wibberley;T. Shimamoto
中科院分区：
文献类型：
--
作者：
C. Wibberley;T. Shimamoto
当断层在其滑动的早期阶段以比驱动断层运动的构造应力释放更快的速度减弱时，地震就发生了。这种滑移减弱发生在一个临界距离，DC。然而，理解对脱氧核糖核酸性质的控制是非常有限的，因为减弱的物理机制是不受限制的。通常在慢滑动速率和小位移下进行的常规摩擦实验得到的Dc值比从天然地震的模拟地震数据估计的值低一个数量级。本文介绍了日本中央构造线断裂带中央滑动带岩石的流体输运性质和滑动带宽度的数据。我们表明，如果孔隙流体的热压作用是滑动弱化机制，那么实验室和地震学结果之间的差异是可以解决的。我们的分析表明，具有不透水的窄滑移带的平面断层段在滑动过程中将变得非常不稳定，很可能是地震凹凸处。
An earthquake occurs when a fault weakens during the early portion of its slip at a faster rate than the release of tectonic stress driving the fault motion,. This slip weakening occurs over a critical distance,Dc. Understanding the controls onDcin nature is severely limited, however, because the physical mechanism of weakening is unconstrained. Conventional friction experiments, typically conducted at slow slip rates and small displacements, have obtainedDcvalues that are orders of magnitude lower than values estimated from modelling seismological data for natural earthquakes,,,. Here we present data on fluid transport properties of slip zone rocks and on the slip zone width in the centre of the Median Tectonic Line fault zone, Japan. We show that the discrepancy between laboratory and seismological results can be resolved if thermal pressurization of the pore fluid,,,is the slip-weakening mechanism. Our analysis indicates that a planar fault segment with an impermeable and narrow slip zone will become very unstable during slip and is likely to be the site of a seismic asperity.