Large Earthquake Triggering, Clustering, and the Synchronization of Faults
Large Earthquake Triggering, Clustering, and the Synchronization of Faults
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DOI：
10.1785/0120090309
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发表时间：
2010-06-01
影响因子：
3
通讯作者：
Scholz, Christopher H.
中科院分区：
文献类型：
--
作者：
Scholz, Christopher H.
有时观察到大地震会在附近断层上引发其他大地震。计算出的库仑应力转移的大小（推测会导致触发）为地震应力降的 10(-2)-10(-3)。相对于地震的自然重现时间，地震应力降和触发延迟时间同样较小。这要求两个断层同时非常接近其地震周期的末端。古地震学数据表明，对于同一地区，先前的地震是在由长静止期分隔开的几个断层的破裂集中发生的。这两个观察结果都表明故障之间正在发生同步。理论和观察表明，在夹带阈值内具有正应力耦合和固有滑移速度的附近断层之间可以发生同步。在冰岛南部地震带、内华达中部地震带和加利福尼亚东部剪切带中，可以识别出几个明显独立作用的同步星团。此行为是锁相的 3D 等效项，锁相导致单个断层的地震周期由大特征地震主导，并且使断层段沿给定断层同步。重复的单个地震或地震群的破裂模式在 2D 或 3D 情况下都不相同。该系统的状态表现出强烈的同步迹象，但没有精确的重复，可以称为模糊同步。
Large earthquakes are sometimes observed to trigger other large earthquakes on nearby faults. The magnitudes of the calculated Coulomb stress transfers presumed to cause the triggering are 10(-2)-10(-3) of the earthquake stress drops. The earthquake stress drops and the triggering delay times are similarly small with respect to the natural recurrence time of the earthquakes. This requires that both faults be simultaneously very close to the ends of their seismic cycles. Paleoseismological data show that for the same regions prior earthquakes have occurred in clusters of ruptures of several faults separated by long quiescent periods. Both observations suggest that synchronization is occurring between faults. Theory and observations indicate that synchronization can occur between nearby faults with positive stress coupling and intrinsic slip velocities within an entrainment threshold. In the south Iceland seismic zone, the central Nevada seismic belt, and the eastern California shear zone, several synchronous clusters that apparently act independently can be recognized. This behavior is the 3D equivalent of the phase locking that results in the seismic cycle of individual faults being dominated by large characteristic earthquakes, and for synchronization of fault segments along a given fault. Rupture patterns of repeated individual earthquakes or earthquake clusters are not identical in either the 2D or 3D cases. The state of this system, which exhibits strong indications of synchrony without exact repetition, may be called fuzzy synchrony.