The number of earthquakes in the western Canada sedimentary basin (WCSB) has increased drastically in the last decade related to unconventional energy production. The majority of reported earthquakes are correlated spatially and temporally with hydraulic fracturing (HF) well stimulation. In this study, we use waveform data from a new deployment of 15 broadband seismic stations in a spatial area of roughly 60×70km2⁠, covering parts of the Montney Formation, to study the relationship between earthquakes and HF operations in the Dawson‐Septimus area, British Columbia, Canada, where the two largest HF‐related earthquakes in WCSB to date, an Mw 4.6 on 17 August 2015 and an ML 4.5 on 30 November 2018, have occurred. We use an automated short‐term average/long‐term average algorithm and the SeisComP3‐software to detect and locate 5757 local earthquakes between 1 July 2017 and 30 April 2019. Using two clustering techniques and double‐difference relocations of the initial catalog, we define event families that are spatially associated with specific wells, and exhibit temporal migration along a horizontal well bore and/or multiple fractures close to wells. Relocated clusters align in two dominant orientations: one roughly perpendicular to the maximum horizontal regional stress direction (⁠SH⁠) and several conjugate structures at low angles to SH⁠. Comparing the two predominant seismicity lineations to regional earthquake focal mechanisms suggests that deformation occurs via thrust faulting with fault strike oriented perpendicular to SH and via strike‐slip faulting with strike azimuth at low angles to SH⁠. Local scale seismicity patterns exhibit clustering around individual HF wells, whereas regional scale patterns form lineations consistent with deformation on faults optimally oriented in the regional stress field.

中文翻译：

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加拿大不列颠哥伦比亚省东北部Dawson-Septimus地区水力压裂引起的地震星团的高分辨率成像

在过去十年中，与非常规能源生产有关的加拿大西部沉积盆地（WCSB）地震数量急剧增加。大多数报道的地震在空间和时间上与水力压裂（HF）井增产相关。在这项研究中，我们使用新的15个宽带地震台站的波形数据，在约60×70km2的空间区域覆盖蒙尼组的部分区域，研究了道森-西普提姆斯地区地震与高频作业之间的关系在加拿大不列颠哥伦比亚省，发生了迄今为止WCSB两次最大的与HF有关的地震，2015年8月17日发生了4.6兆瓦，2018年11月30日发生了ML 4.5。我们使用自动化的短期平均/长期平均算法和SeisComP3软件在2017年7月1日至2019年4月30日之间检测和定位5757次本地地震。使用两种聚类技术和初始目录的双差重定位，我们定义与特定井在空间上相关的事件族，并显示沿水平井眼的时间偏移和/或靠近井的多个裂缝。重定位的簇在两个主要方向上对齐：一个大致垂直于最大水平区域应力方向（⁠SH⁠）和几个与SH⁠低角度的共轭结构。将这两个主要地震活动线与区域地震震源机制进行比较表明，变形是通过与南北向垂直的断层走向的逆冲断层和与南北向低角度的走滑方位角的走滑断层发生的。局部尺度的地震活动模式表现出在单个HF井周围的聚集，而区域尺度的活动模式形成的线条与区域应力场中最佳定向的断层的变形相一致。