A 667 year record of coseismic and interseismic Coulomb stress changes in central Italy reveals the role of fault interaction in controlling irregular earthquake recurrence intervals
A 667 year record of coseismic and interseismic Coulomb stress changes in central Italy reveals the role of fault interaction in controlling irregular earthquake recurrence intervals
复制标题
意大利中部 667 年同震和震间库仑应力变化记录揭示了断层相互作用在控制不规则地震复发间隔中的作用
DOI：
10.1002/2017jb014054
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发表时间：
2017
期刊：
影响因子：
3.4
通讯作者：
Wedmore L
中科院分区：
文献类型：
--
作者：
Wedmore L
目前的断层相互作用的研究缺乏足够长的地震记录和测量断层滑动速率在多个地震周期，充分调查的影响，地震间的负载和同震应力变化对周围的断层网络。我们模拟了自公元1349年以来意大利中部30次地震的97个断层之间的弹性相互作用，以研究地震发生和断层相互作用的同震应力变化与震间应力积累的相对重要性。该地区有着667年的历史地震记录，并对其活动正断层的位置和滑动速率进行了详细的限制。在1654年以来的21次地震中，有20次地震发生在同震和震间载荷应力为正的断层上，尽管在任何一个时间，约20%的断层处于“应力阴影”中。此外，经历地震的断层上的库仑应力在统计上不同于该地区随机地震序列。我们展示了同震库仑应力的变化是如何改变地震间隔时间的~ 103年，断层长度控制了这种影响的强度。静态库仑应力的变化会导致更大的intervent扰动较短的断层在地区的特点是较低的应变（或滑动）率。我们模拟的地震的特殊持续时间和数量使我们能够证明将长地震记录与断层几何形状，滑动速率和运动学的详细知识相结合的重要性，以了解复杂的活动断层网络中应力变化的影响。
Current studies of fault interaction lack sufficiently long earthquake records and measurements of fault slip rates over multiple seismic cycles to fully investigate the effects of interseismic loading and coseismic stress changes on the surrounding fault network. We model elastic interactions between 97 faults from 30 earthquakes since 1349 A.D. in central Italy to investigate the relative importance of co‐seismic stress changes versus interseismic stress accumulation for earthquake occurrence and fault interaction. This region has an exceptionally long, 667 year record of historical earthquakes and detailed constraints on the locations and slip rates of its active normal faults. Of 21 earthquakes since 1654, 20 events occurred on faults where combined coseismic and interseismic loading stresses were positive even though ~20% of all faults are in “stress shadows” at any one time. Furthermore, the Coulomb stress on the faults that experience earthquakes is statistically different from a random sequence of earthquakes in the region. We show how coseismic Coulomb stress changes can alter earthquake interevent times by ~103years, and fault length controls the intensity of this effect. Static Coulomb stress changes cause greater interevent perturbations on shorter faults in areas characterized by lower strain (or slip) rates. The exceptional duration and number of earthquakes we model enable us to demonstrate the importance of combining long earthquake records with detailed knowledge of fault geometries, slip rates, and kinematics to understand the impact of stress changes in complex networks of active faults.