Deciphering the influence of rock properties on fault rupture mechanics

解读岩石性质对断层破裂力学的影响

• 批准号: RGPIN-2015-04255
• 负责人: Harrington, Rebecca
• 金额: $ 1.31万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612860
• 关键词: Deciphering; influence; rock; properties; fault

Earthquakes are the dominant mechanism accommodating motion on faults. The speed at which an earthquake rupture propagates is the key parameter determining associated seismic hazard. Recent observations suggest that rupture speed occurs over a continuum of time scales, but there is little understanding of how the physical conditions on the fault where an earthquake occurs control rupture speed, and thus, seismic hazard. This research program aims over the long term to study what physical factors on the fault surface, such as rock composition, degree of damage, concentration of fluids, etc., are most critical to controlling rupture speed, so that we can better assess the risk to society posed by earthquakes, and mitigate seismic hazard. Over the next five years, the proposed research program will concentrate on resolving rupture behavior in the context of bulk fault frictional properties by addressing a critically important question: How do changing frictional properties with depth modulate the rupture velocity on a fault? To address this question, research efforts will be concentrated in three main areas that investigate rupture speed and its relation to fault surface friction over the shallow (< 2 km), intermediate (2-15 km), and deep (15-35 km) portions of fault zones. The program will have a broad impact on the mechanistic understanding of earthquake rupture physics on a basic scientific level, and will provide practical tools for better anticipating and assessing seismic hazard in Canada, and elsewhere. Current methods for estimating seismic hazard are based on limited empirical observations of ground motion with a wide range of outliers, and lack fundamental information about the earthquake rupture itself. Quantifying the link between changing frictional differences on fault surfaces and the changes in earthquake rupture properties is key to developing better seismic hazard estimates. This program will help improve seismic hazard assessment and subsequent societal risk by linking fault properties to rupture speed. In particular, it will contribute to better hazard assessment of anthropogenically induced earthquakes, an increasing concern in Canada due to the proliferation of non-conventional oil and gas recovery techniques.

地震是调节断层运动的主要机制。地震破裂传播的速度是决定相关地震危险性的关键参数。最近的观察表明，破裂速度发生在一个连续的时间尺度上，但对于地震发生的断层上的物理条件如何控制破裂速度，从而造成地震危险，人们几乎不了解。这项研究计划旨在长期研究断层表面的哪些物理因素，如岩石成分、破坏程度、流体浓度等，对控制破裂速度最关键，以便我们能够更好地评估地震对社会构成的风险，减轻地震灾害。 在接下来的五年里，拟议的研究计划将集中在整体断层摩擦特性的背景下解决破裂行为，通过解决一个至关重要的问题：随着深度变化的摩擦特性如何调节断层上的破裂速度？为了解决这个问题，研究工作将集中在三个主要领域，调查断裂速度及其与断裂带浅(2公里)、中(2-15公里)和深(15-35公里)部分断层表面摩擦的关系。该计划将在基础科学水平上对地震破裂物理的机制理解产生广泛影响，并将为更好地预测和评估加拿大和其他地方的地震危险提供实用工具。目前估计地震危险性的方法是基于对地面运动的有限的经验观测，具有很大范围的异常值，并且缺乏关于地震破裂本身的基本信息。量化断层表面摩擦差异变化与地震破裂性质变化之间的联系是开发更好的地震危险性估计的关键。通过将断层属性与破裂速度联系起来，该计划将有助于改进地震危险性评估和后续的社会风险。特别是，它将有助于更好地评估人为地震的危险，由于非常规石油和天然气开采技术的扩散，这在加拿大越来越令人担忧。