How faults wake up: The Guthrie-Langston, Oklahoma earthquakes
How faults wake up: The Guthrie-Langston, Oklahoma earthquakes
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断层如何苏醒：俄克拉荷马州格思里-兰斯顿地震
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
W. Ellsworth
中科院分区：
文献类型：
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作者：
M. Schoenball;F. R. Walsh;M. Weingarten;W. Ellsworth
作者：Schoenball， M；沃尔什,FR;温加滕,M;摘要：©2018 by The Society of Exploration geophysics。大规模的废水处理导致俄克拉何马州/堪萨斯州地区断层的快速复苏。高分辨率地震重新定位表明，研究区古基底断裂的清查结果与以沉积盖层为中心的地震调查和地质填图结果不同。我们更详细地分析了俄克拉何马州中部格思里-兰斯顿序列地震活动的演变。在这里，地震活动已经在一个直径不到10公里的地区重新激活了一个由至少12个亚垂直断层组成的网络。有记录的地震活动始于2013年底，在大约6个月后达到峰值，其中包括两次4级地震。这些地震的特点是发生在基底顶部以下约4公里的深度，没有到达沉积盖层。该序列显示出径向增长模式，尽管距离重要的废水处理活动不超过10公里。水文模拟表明，相对于早期注入活动，活动开始的时间滞后了几年。地震相互作用一旦开始，就会促使地震活动性沿着重新激活的断层传播。因此，地震活动的时空演变模拟了一种扩散模式，这种模式通常被认为与注入活动有关。对断层滑动电位的分析表明，在现代应力场中，大多数断层处于临界应力状态。在一些断层上的活动，我们发现滑动概率很低，这表明地质力学非均质性对这些古老基底断层的重新觉醒有重要贡献。
Author(s): Schoenball, M; Walsh, FR; Weingarten, M; Ellsworth, WL | Abstract: © 2018 by The Society of Exploration Geophysicists. Large-scale wastewater disposal has led to a fast-paced reawakening of faults in the Oklahoma/Kansas region. High-resolution earthquake relocations show that the inventory of ancient basement faults in the study region differs from results of seismic surveys and geologic mapping focused on the sedimentary cover. We analyze the evolution of seismic activity in the Guthrie-Langston sequence in central Oklahoma in greater detail. Here, seismic activity has reactivated a network of at least 12 subvertical faults in an area less than 10 km across. Recorded activity began in late 2013, peaked about six months later, and includes two M 4 earthquakes. These earthquakes characteristically occur at about 4 km depth below the top of the basement and do not reach the sedimentary cover. The sequence shows a radial growth pattern despite being no closer than 10 km to significant wastewater disposal activity. Hydrologic modeling suggests that activity initiated with a time lag of several years relative to early injection activity. Once initiated, earthquake interactions contribute to the propagation of seismicity along the reactivated faults. As a result, the spatiotemporal evolution of the seismicity mimics a diffusive pattern that is typically thought to be associated with injection activity. Analysis of the fault slip potential shows that most faults are critically stressed in the contemporary stress field. Activity on some faults, for which we find low slip probability, suggests a significant contribution of geomechanical heterogeneities to the reawakening of these ancient basement faults.