RAPID: Collaborative Research: Seismic Response to the 2016 M5.8 Pawnee Earthquake

自2009年以来，美国中西部地区的诱发地震或由废水注入或二次采油等人类活动引起的地震活动一直在增加。 俄克拉荷马州被称为“新的地震之都”，在过去的几年里，M3级地震的发生率超过了加州。2016年9月3日，俄克拉荷马州波尼Mw 5.8地震发生在诱发地震活动区域内，靠近废水处理威尔斯井，是该州有记录以来最大的地震。这次地震发生在第二大地震五年后，2011年11月布拉格发生了同样规模的5.7级地震。波尼附近的当地居民报告说，地面发生强烈震动，房屋受损，地面出现裂缝，并对安全表示担忧。康奈尔大学和哥伦比亚大学的学生与包括俄克拉荷马州大学、俄克拉荷马州州立大学和塔尔萨大学在内的当地大学合作，积极参与了在震中地区周围快速部署25个地震台站的工作。相关机构的学生积极参与传感器、网络设计和地震物理学的学习。波尼事件期间破裂的主要断层是一个未映射的断层，与映射的Labette断层相交，该断层承载了大量的余震，包括最大的余震（M3.9）。自快速（2天内）部署地震仪器以来记录的该区域的余震序列和相关地震活动将有助于 研究区域断层系统的余震和可能引发的地震活动。在未来几周内，我们将部署另外20个短期站，记录12个月的数据。这个组合网络将提供有关断层结构、余震衰减、持续时间以及与注入率变化的相互作用的信息。这些数据将有助于了解承载大破坏性地震的断层的特征，并将有助于评估俄克拉荷马州和中部大陆的地震危险。这种快速部署的更广泛影响将有助于了解北方俄克拉荷马州的区域构造框架，并可能阐明最近的地震活动与该地区的流体注入活动之间的关系。

Induced earthquakes, or seismicity caused by human activity such as wastewater injection or secondary oil recovery, have been increasing in the midwestern United States since 2009. The state of Oklahoma has become known as "the new earthquake capital", with earthquake rates of M3 exceeding those of California in the last few years. The 3 September 2016 Mw5.8 Pawnee, Oklahoma earthquake occurred within the region of induced seismicity, near wastewater disposal wells, and was the largest earthquake ever recorded within the state. The earthquake occurred five years after the second largest earthquake, the similarly sized Mw5.7 November 2011 Prague earthquake. Near Pawnee, local residents reported strong ground-shaking, damage to houses, cracks on the ground, and concerns about safety. Students from Cornell University and Colombia University, in collaboration with local universities including the University of Oklahoma, Oklahoma State University, and University of Tulsa, actively participated in the rapid deployment of 25 seismic stations around the epicentral region. Students of the institutions involved have been actively involved in learning about sensors, network designs, and earthquake physics. The main fault the ruptured during the Pawnee event was an unmapped fault intersecting mapped Labette Fault, which has hosted a significant number of aftershocks include the largest aftershock (M3.9). The aftershock sequence and related seismic activity in the region that has been recorded since the rapid (within 2 days) deployment of seismic instrumentation will help study aftershocks and the likely triggered seismicity on the regional fault systems. In the coming weeks, we will deploy an additional 20 short-period stations that will record data for 12 months. This combined network will provide information on fault structure, aftershock decay, duration, and interaction with injection rate variations. The data will help to understand the characteristics of faults that host large damaging earthquakes, and will help to assess earthquake hazards in Oklahoma and the midcontinent. The broader impact of this rapid deployment will help understand the regional tectonic framework in northern Oklahoma and may elucidate the relationship between this recent seismic activity with the fluid injection activities in the region.