Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology, MC 252-21, 1200 E California Boulevard, Pasadena, California 91125, USA.
Mechanical and Civil Engineering, Division of Engineering and Applied Science, California Institute of Technology, MC 252-21, 1200 E California Boulevard, Pasadena, California 91125, USA.
Nat Commun. 2016 Oct 5;7:13020. doi: 10.1038/ncomms13020.
Studying small repeating earthquakes enables better understanding of fault physics and characterization of fault friction properties. Some of the nearby repeating sequences appear to interact, such as the 'San Francisco' and 'Los Angeles' repeaters on the creeping section of the San Andreas Fault. It is typically assumed that such interactions are induced by static stress changes due to coseismic slip. Here we present a study of the interaction of repeating earthquakes in the framework of rate-and-state fault models using state-of-the-art simulation methods that reproduce both realistic seismic events and long-term earthquake sequences. Our simulations enable comparison among several types of stress transfer that occur between the repeating events. Our major finding is that postseismic creep dominates the interaction, with earthquake triggering occurring at distances much larger than typically assumed. Our results open a possibility of using interaction of repeating sequences to constrain friction properties of creeping segments.
研究小的重复地震可以更好地了解断层物理特性，并对断层摩擦特性进行描述。一些附近的重复序列似乎存在相互作用，例如圣安德烈亚斯断层蠕动段上的“旧金山”和“洛杉矶”重复序列。通常认为这种相互作用是由同震滑动引起的静态应力变化引起的。在这里，我们使用最先进的模拟方法，在速率状态断层模型的框架内研究重复地震的相互作用，该方法可以再现真实的地震事件和长期地震序列。我们的模拟能够比较重复事件之间发生的几种类型的应力传递。我们的主要发现是，余震蠕动主导了相互作用，地震触发发生的距离远远大于通常假设的距离。我们的结果为利用重复序列的相互作用来约束蠕动段的摩擦特性提供了可能性。
