Linking earthquake seismicity to underlying fault structure from studies of simple models

大地震作为一种自然灾害，对今天加拿大东部和西部的城市人口构成了几乎无法理解和无法估量的风险。但是，通过更好地了解地震灾害，可以减少地震损失，这是防备和减灾的先决条件。我的研究计划的目标是提供对控制自然和人为灾害的过程的全面理解，特别是那些产生地震的过程，从而提高对区域地震灾害的相关估计。这项建议的长期目标是将地震断层的潜在物理特征与在自然地震活动中观察到的空间和时间模式联系起来，特别是那些控制震级、位置和复发的模式。短期目标是提供损伤和断层力学对自然地震时空聚类影响的定量测量，并定义断层表面性质（如应力分布或摩擦系数）与相关地震和大地测量时程之间的关系。研究表明，更大、更强的凸起会产生更大的事件，并与地震风险增加有关。在这里，从自然和合成时间序列中对震级频率关系、前震-余震持续时间和事件间时间的研究将从简单断层和断层网络的计算机模拟中为断层表面的力学提供宝贵的见解。该研究项目将首次利用历史地震记录将研究扩展到自然地震断层。这里要解决的主要问题是：地震活动性的统计数据——一种今天很容易准确测量的现象——与控制最大地震的震级、位置和发生时间的断层参数之间的关系是什么？新的成果包括通过改进对影响其短期和长期行为的物理因素的量化，更好地了解大地震发生前的物理过程。量化大地震前兆动力学的能力是我们评估未来事件的震级和可能性的基础，使我们能够显著提高其可预测性，并更准确地评估随时间变化的地震危害。

Large earthquakes, as a natural disaster, represent an almost incomprehensible and incalculable risk to today’s urban populations in both eastern and western Canada. However, earthquake losses can be reduced through better knowledge of earthquake hazard, a prerequisite for preparation and mitigation. The goal of my research program is to provide a comprehensive understanding of the processes which govern natural and anthropogenic hazards and, in particular, those which generate earthquakes, and thus improve the associated estimates of regional seismic hazard. The long-term objective of this proposal is to link the underlying physical characteristics of an earthquake fault to the spatial and temporal patterns observed in natural seismicity, particularly those that govern the magnitude, location and recurrence. The short-term objectives are to provide quantitative measures of the effect of damage and fault mechanics on the spatial and temporal clustering in natural earthquakes and to define the relationship between fault surface properties, such as stress distribution or friction coefficient, and the associated seismic and geodetic time histories. Studies suggest that larger, stronger asperities produce bigger events and are associated with increased seismic hazard. Here, studies of the magnitude-frequency relation, foreshock-aftershock duration, and interevent time from natural and synthetic time series will provide invaluable insights into the mechanics of the fault surface from computer simulations of both simple faults and fault networks. This research program will, for the first time, extend this research to natural earthquake faults using historical seismic records. The primary question to be addressed here is: What is the relationship between the statistics of earthquake seismicity – a phenomenon that is easily and accurately measured today – and the fault parameters that control the magnitude, location and time-of-occurrence of the largest events? New outcomes include a better understanding of the physical process preceding the occurrence of large earthquakes through improved quantification of the physical factors that affect their short- and long-term behavior. The ability to quantify the precursory dynamics for large earthquakes is fundamental to our ability to assess both the magnitude and likelihood of future events, allowing us to significantly improve their predictability and more accurately assess the time-dependent seismic hazard.