An integrated study of induced earthquakes and crust-mantle seismic structure

地震可分为两大类：一类是由构造力引起的地震，通常称为天然地震；另一类是由采矿、碳氢化合物生产或流体注入/回流等人类活动引发的地震。天然地震有各种大小、深度和震级，与之相关的地震波已被广泛用于推断地球内部的结构。另一方面，人为源，也被称为诱发地震，人们对此了解较少，但报告的频率和规模都在增加。艾伯塔省中部和西部最近发生的地震是与废水处理和水力压裂(简称水力压裂)作业有关的引人注目的案例。 未来几年拟议的研究计划将针对加拿大西部沉积盆地(WCSB)的地震风险和不同空间尺度的结构。拟议计划的区域部分将结合被动震源部署与基于实验室的地震风险和结构分析。它将通过分析诱发地震的震源特征和来源，利用增加的台站密度和覆盖率。它还旨在提供加拿大西部地下三维地震速度的更新、更准确的地图。与诱发地震有关的预期研究成果可能会直接影响对艾伯塔省持续经济增长至关重要的环境政策和决策。该区域地震台阵的广泛数据库也为解决有关北美大陆地壳和地幔地震结构和构造史的科学问题提供了难得的机会。 这一区域研究部分将得到以实验室为基础的全球地震数据分析的补充。有关地壳/地幔界面深度和强度的地震学观测提供了矿物物理、地震学和热/成分条件之间的重要联系。宽带数据和基于阵列的成像方法的可获得性将使各种构造体制下的地壳和地幔的高分辨率快照成为可能。拟议的研究将利用高频方法(例如，P‘P’前兆)，结合全波形反演和频谱分解方法，以获得典型的有源实验类型的分辨率。 拟议研究方案的两个组成部分在规模和范围上是互补的。它们共同构成了对加拿大西部地震风险的长期研究以及古代大陆和最近形成的板块边界带的历史/动力学的坚实基础。拟议的方案将是现有研究生和其他高素质人员培训的一个组成部分。

Earthquakes can be categorized into two main groups: ones that occur as a result of tectonic forces, often referred to as natural earthquakes, and ones that are triggered by human activities such as mining, hydrocarbon production or fluid injection/withdrawal. Natural earthquakes come in all sizes, depths and magnitudes, and the seismic waves associated with them have been widely utilized to infer the structure of the Earth’s interior. On the other hand, anthropogenic sources, also known as induced earthquakes, are less well understood but are being reported at increasing frequencies and sizes. Recent earthquakes in central and western Alberta are compelling case studies in connection with wastewater disposal and hydraulic fracturing (for short, ‘fracking’) operations. The proposed research program in the upcoming years will target both seismic risks in the Western Canada Sedimentary Basin (WCSB) and structures at different spatial scales. The regional component of the proposed program will combine passive-source deployments with laboratory-based analyses of seismic risk and structure. It will take advantage of increased station density and coverage by analyzing the source characteristics and origins of induced earthquakes. It also aims to provide an updated, more accurate map of three-dimensional seismic velocity beneath western Canada. Expected research outcomes pertaining to induced earthquakes may directly impact the environmental policies and decisions vital for the sustained economic growth in the province of Alberta. The extensive database from this regional seismic array also presents a rare opportunity to address scientific issues regarding the crust and mantle seismic structure and the tectonic history of the North American continent. This regional research component will be complemented by a laboratory-based, global analysis of earthquake data. Seismological observations pertaining to the depths and strengths of crust/mantle interfaces provide a crucial link between mineral physics, seismology and thermal/compositional conditions. The availability of broadband data and array-based imaging methods will enable high-resolution snapshots of the crust and mantle beneath various tectonic regimes. The proposed research will utilize high frequency methods (e.g., P'P' precursors), in combination with full waveform inversion and spectral decompositional approaches, to achieve the type of resolution typical of active-source experiments. The two components of the proposed research program are complementary in scale and scope. Together, they form a solid foundation for long-term studies of seismic risks in western Canada and the history/dynamics of both ancient landmasses and more recently formed plate boundary zones. The proposed program will be an integral part of the training of existing graduate students and other highly qualified personnel.