Mildon Z K, Roberts G P, Faure Walker J P, Toda S
School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK.
Institute for Risk and Disaster Reduction, University College London, Gower Street, London, WC1E 6BT, UK.
Nat Commun. 2019 Jun 21;10(1):2744. doi: 10.1038/s41467-019-10520-6.
Successive locations of individual large earthquakes (M > 5.5) over years to centuries can be difficult to explain with simple Coulomb stress transfer (CST) because it is common for seismicity to circumvent nearest-neighbour along-strike faults where coseismic CST is greatest. We demonstrate that Coulomb pre-stress (the cumulative CST from multiple earthquakes and interseismic loading on non-planar faults) may explain this, evidenced by study of a 667-year historical record of earthquakes in central Italy. Heterogeneity in Coulomb pre-stresses across the fault system is >±50 bars, whereas coseismic CST is <±2 bars, so the latter will rarely overwhelm the former, explaining why historical earthquakes rarely rupture nearest neighbor faults. However, earthquakes do tend to occur where the cumulative coseismic and interseismic CST is positive, although there are notable examples where earthquake propagate across negatively stressed portions of faults. Hence Coulomb pre-stress calculated for non-planar faults is an ignored yet vital factor for earthquake triggering.
在数年至数百年间，单个大地震（震级M>5.5）的连续发生地点可能难以用简单的库仑应力转移（CST）来解释，因为地震活动避开同震CST最大的沿走向最近邻断层是很常见的。我们证明，库仑预应力（多次地震产生的累积CST以及非平面断层上的震间加载）或许可以解释这一现象，意大利中部667年的地震历史记录研究证明了这一点。整个断层系统中库仑预应力的不均匀性>±50巴，而同震CST<±2巴，所以后者很少会超过前者，这就解释了为什么历史地震很少会使最近邻断层发生破裂。然而，地震确实倾向于发生在同震和震间CST累积为正的地方，不过也有明显的例子表明地震会穿过断层负应力部分。因此，为非平面断层计算的库仑预应力是地震触发中一个被忽视但至关重要的因素。
Zotero 插件