Earthquake rupture mechanisms from induced events to megathrusts

从诱发事件到巨型逆冲的地震破裂机制

• 批准号: RGPIN-2017-04118
• 负责人: Dettmer, Jan
• 金额: $ 2.33万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710030
• 关键词: Earthquake; rupture; mechanisms; induced; events

This research program advances understanding of earthquake processes at scales from tsunamigenic megathrusts to induced seismicity and improves seismic hazard mitigation and response in Canada and worldwide. In the long-term, this knowledge will contribute to the fundamental understanding of earthquake cycles. Tsunamigenic earthquakes are a major hazard, as tragically documented by devastating events (e.g. Indian Ocean, Japan). While high-quality data are increasingly available, significant gaps in methods and understanding exist. Although induced earthquakes are not associated with devastation, significant concerns exist that they can cause damage and little is known about the governing processes and scales. Here, state-of-the-art Bayesian inversion and high-performance computing are brought together to tackle two key areas of earthquake source studies: (1) Imaging the spatiotemporal evolution of rupture on faults (finite fault inversion, FFI) and (2) studying rupture complexity (source-time function, rupture of multiple segments) with point-source models as centroid moment tensors (CMT) including higher-order tensors. (1) My research shows that more-robust FFI results are obtained by employing quantitative Bayesian model selection to eliminate subjective choices about fault discretization. However, the effects of fault geometry, sensor coverage and rupture complexity on slip resolution are still unknown. This program will apply Bayesian model selection to all aspects of the fault (size, discretization, orientation) and to data-noise parameters to address these shortcomings. (2) Similarly, CMT inversion is plagued by non-uniqueness and subjective parametrization choices, such as fixing event depth, which often obfuscate interpretation. We will study these issues by non-linear uncertainty quantification of CMT parameters and centroid location. In addition, model selection will be applied to rupture complexity by considering multiple centroids and higher-order tensors. Both research focuses will be applied to geodetic (GPS, seafloor GPS, high-rate GPS, LiDAR), seismic, and tsunami data and to microseismic borehole and surface observations. This research can overcome current limitations of source studies and provide more rigorous, objective results that enhance credibility of tectonic and seismic interpretations. To achieve these goals, I will strengthen my existing national and international collaboration with leading institutions (Australian National U. - ANU, Geoscience Australia, NRCan, UVic) and industry partners (Microseismic Industry Consortium) to provide high-quality HQP training. The training effort is structured to produce quantifiable research and training outcomes in the form of peer-reviewed articles, conference presentations, and practical methods that improve seismic hazard assessment and early warning.

该研究计划推进了对地震过程的理解，从海啸巨型推力到诱发地震活动，并改善了加拿大和世界各地的地震灾害缓解和响应。从长远来看，这些知识将有助于对地震周期的基本理解。海啸引发的地震是一种主要的危害，正如灾难性事件（例如印度洋，日本）所记录的那样。虽然高质量的数据越来越多，但在方法和理解方面存在重大差距。虽然诱发地震与破坏无关，但存在重大关切，即它们可能造成破坏，而且对控制过程和规模知之甚少。 在这里，最先进的贝叶斯反演和高性能计算相结合，以解决震源研究的两个关键领域：（1）成像断层上破裂的时空演化（有限断层反演，FFI）和（2）研究破裂的复杂性（源-时间函数，多段破裂）与点源模型作为质心矩张量（CMT），包括高阶张量。 (1)我的研究表明，更强大的FFI结果，通过采用定量贝叶斯模型选择，以消除主观选择故障离散化。然而，断层的几何形状，传感器的覆盖范围和破裂的复杂性对滑动分辨率的影响仍然是未知的。该程序将贝叶斯模型选择应用于故障的所有方面（大小，离散化，方向）和数据噪声参数，以解决这些缺点。 (2)同样，CMT反演也受到非唯一性和主观参数化选择的困扰，例如固定事件深度，这通常会混淆解释。我们将通过CMT参数和质心位置的非线性不确定性量化来研究这些问题。此外，通过考虑多个质心和高阶张量，将模型选择应用于破裂复杂性。这两个研究重点都将应用于大地测量（全球定位系统、海底全球定位系统、高速率全球定位系统、激光雷达）、地震和海啸数据以及微震钻孔和地表观测。 这项研究可以克服目前震源研究的局限性，提供更严格，客观的结果，提高构造和地震解释的可信度。为了实现这些目标，我将加强与领先机构（澳大利亚国立大学）现有的国家和国际合作。- 澳大利亚国立大学，澳大利亚地球科学，NRCan，UVic）和行业合作伙伴（微震行业联盟）提供高质量的HQP培训。培训工作的结构是以同行评审文章、会议演讲和改进地震灾害评估和预警的实用方法的形式产生可量化的研究和培训成果。