Collaborative research: Investigating effects of geologic complexity on induced seismicity, using M0-M5.7 seismicity from Prague, Oklahoma

最近美国中西部诱发地震活动激增，其间俄克拉何马州的地震活跃率已超过加利福尼亚州，引起了争议，引起了公众的注意，并影响了政策。因此，诱发地震活动已成为近几年来美国地震科学研究的热点，但诱发地震活动的机制仍有待进一步研究。在这项研究中，记录良好的2011年俄克拉荷马州布拉格地震序列将被用来调查地震活动性研究中通常无法获得的规模的形变(地震定位精度约10米)。这种位置良好的地震可以更好地理解复杂断层是如何失效的。此外，对布拉格地区岩石的实验室实验将提供有关断层的强度和稳定性以及向断层中注入流体如何促进地震的信息。布拉格序列包含三次大于MW5的地震及其强大的余震序列，以及两次大地震的前震序列。布拉格地震的定位精度使人们能够在相当于研究出土断层时测量的断层结构的尺度上考虑破裂过程。此外，布拉格地区岩性的补充实验室实验将允许研究流体压力对断层强度和稳定性的影响。最终目标是使用布拉格数据集来探索流体压力和断裂带复杂性对地震成核、传播和阻止的影响。具体地说，这项工作将解决以下问题：1)布拉格附近的断层是否显示出可用于预测破裂的前兆活动？2)复杂的断层几何形状如何控制破裂？3)断层强度、强度不均质性和断层稳定性如何在诱发地震中发挥作用？

The recent surge in induced seismicity in the Midwestern United States, during which Oklahoma has catapulted past California in seismicity rate, has created controversy, captured the attention of the general public, and influenced policy. As a result, induced seismicity has become a focal point of earthquake science in the United States over the last few years; however, much remains to be learned about the mechanisms of induced seismicity. In this research the well-recorded 2011 Prague, OK earthquake sequence will be used to investigate deformation on a scale not commonly obtainable in seismicity studies (earthquake location with precision ~10 meters). Such well-located earthquakes allow for better understanding of how complex faults fail. Furthermore, laboratory experiments on the rocks from the Prague area will provide information on how strong and stable the faults are, and how pumping fluids into the faults might promote earthquakes.The Prague sequence contains three earthquakes greater than Mw5 and their robust aftershock sequences, as well as the foreshock sequences for two large events. The precision with which the Prague earthquakes can be located allows the failure processes to be considered on a scale comparable to fault structures measured in studies of exhumed faults. In addition, complementary laboratory experiments on lithologies from the Prague area will allow study of the effects of fluid pressure on fault strength and stability. The ultimate goal is to use the Prague dataset to probe the influence of fluid pressure and fault zone complexity on earthquake nucleation, propagation, and arrest. Specifically this work will address the following questions: 1) Do the faults near Prague show precursory activity that could be used to forecast rupture? 2) How does complex fault geometry control rupture? and 3) How do fault strength, strength heterogeneity, and fault stability play a role in induced earthquakes?