Collaborative Research: Generation of Rock Damage and Localization of Seismicity Before Large Earthquakes

大地震是如何产生的，以及如何预测它们，仍然是基本的未解决的科学问题。它们对人类社会有着强烈的影响。大地震会造成生命损失、毁灭性破坏，并引发海啸、火灾和山体滑坡等额外的危险。该项目旨在提高对地震动力学的认识和预测大地震的能力。它的关键方面是跟踪地震破裂前地震变形的渐进定位。为了达到这个目的，研究人员将新的统计技术与来自不同构造环境的高分辨率地震目录结合起来。他们考虑了压裂实验和变形局部化物理模型的数据。该项目还为两名研究生提供支持和培训。其结果有助于改进地震危险性评估。调查工作的目的是建立一个定量的操作框架，以跟踪大地震的准备过程。这是通过跟踪变形的渐进演变，从一个体积的分布破坏到局部剪切带，最终产生大地震来完成的。该研究考虑整个体的变形，而不是预先存在的断层或断层集。该分析与在不同时空-能量尺度上对数千个地震群进行统一的区域分析和解释有关，而没有对分析区进行回顾性选择。该项目开发、测试并实施了一个综合多信号程序，该程序综合了可用于估计大地震接近时间的不同地震观测结果。所开发的工具和结果对认识活动构造环境中的地震活动性和分析地震危险性具有重要意义。这项研究可以为地震物理和地震灾害的其他观测、实验和理论研究提供信息和影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

How large earthquakes are generated, and how to forecast them, remain fundamental unsolved scientific questions. They have strong implications for human societies. Large earthquakes can result in loss of life, devastating destruction, and trigger additional hazards such as tsunamis, fires, and landslides. This project aims to improve the understanding of earthquake dynamics and ability to forecast large events. Its key aspect is to track the progressive localization of seismic deformation preceding the earthquake rupture. With this aim, the researchers combine novel statistical techniques with high-resolution earthquake catalogs from different tectonic environments. They account for data from fracturing experiments and physical modeling of deformation localization. The project also provides support and training for two graduate students. Its outcomes contribute to improve earthquake hazard assessment. The investigations work to develop a quantitative operational framework for tracking the preparation processes of large earthquakes. This is done by following the progressive evolution of deformation from distributed failures in a volume to localized shear zones culminating in generation of large earthquakes. The research considers deformation in entire volumes rather than on pre-existing faults or sets of faults. The analysis is associated with uniform regional analysis and interpretation of thousands of earthquake clusters on different space-time-energy scales, without retrospective selection of the analyzed zones. The project develops, tests, and implements an integrated multi-signal procedure synthesizing different seismic observations that may be used to estimate the approaching time of large earthquakes. The developed tools and results can have significant impact on understanding of seismicity and analysis of seismic hazard in active tectonic environments. The research can inform and impact additional observational, experimental, and theoretical studies on earthquake physics and seismic hazard.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.