Shear‐wave splitting and earthquake forecasting
Shear‐wave splitting and earthquake forecasting
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DOI：
10.1111/j.1365-3121.2008.00836.x
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发表时间：
2008-12
期刊：
影响因子：
2.4
通讯作者：
Yuan Gao;S. Crampin
中科院分区：
文献类型：
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作者：
Yuan Gao;S. Crampin
地震横波分裂（SWS）监测流体饱和微裂纹岩石的低水平变形。我们报告了系统SWS变化的证据，记录在小地震之上，监测地震前的应力积累，从而可以预测即将发生的大地震的时间和震级。在大约15次地震之前，从冰岛的M1.7地震群事件到台湾的M7.7集集地震，包括冰岛西南部M5.0地震的成功应力预测，已经看到了这种影响。在大地震前观察到SWS时间延迟的特征增加，在地震发生前不久突然改变为减少。大临震前SWS时间延迟的增加和减少的持续时间的幅值和均方根值之间存在线性关系。然而，对于常规的应力预测来说，适当持续的小地震群太稀少了。可靠的预测需要在应力监测点（SMS）的相邻钻孔之间进行受控源跨孔地震。通过一个全球短信网络，可以真实的实时地对世界范围内的破坏性地震进行应力预测。
Seismic shear‐wave splitting (SWS) monitors the low‐level deformation of fluid‐saturated microcracked rock. We report evidence of systematic SWS changes, recorded above small earthquakes, monitoring the accumulation of stress before earthquakes that allows the time and magnitude of impending large earthquakes to be stress‐forecast. The effects have been seen with hindsight before some 15 earthquakes ranging in magnitude from an M1.7 seismic swarm event in Iceland to the Ms7.7 Chi‐Chi Earthquake in Taiwan, including a successfully stress‐forecast of a M5.0 earthquake in SW Iceland. Characteristic increases in SWS time‐delays are observed before large earthquakes, which abruptly change to deceases shortly before the earthquake occurs. There is a linear relationship between magnitudes and logarithms of durations of both increases and decreases in SWS time‐delays before large impending earthquakes. However, suitably persistent swarms of small earthquakes are too scarce for routine stress‐forecasting. Reliable forecasting requires controlled‐source cross‐hole seismics between neighbouring boreholes in stress‐monitoring sites (SMS). It would be possible to stress‐forecast damaging earthquakes worldwide by a global network of SMS in real time.