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

如何产生大地震，以及如何预测它们，仍然是基本的悬而未决的科学问题。它们对人类社会有着强烈的影响。大地震可能导致生命损失、毁灭性破坏，并引发其他危险，如海啸、火灾和山体滑坡。该项目旨在提高对地震动力学的理解和预测大事件的能力。它的关键是跟踪地震破裂前地震形变的渐进局部化。出于这个目的，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相结合。他们解释了来自压裂实验和变形局部化的物理模型的数据。该项目还为两名研究生提供支持和培训。其成果有助于改进地震风险评估。这些调查工作是为了制定一个量化的业务框架，以跟踪大地震的孕育过程。这是通过遵循形变从体积分布的破坏到局部剪切带的渐进演变来实现的，最终导致大地震的发生。这项研究考虑的是整个体积的变形，而不是先前存在的断层或断层集。这种分析涉及对不同时空-时间-能量尺度上的数千个地震群进行统一的区域分析和解释，而不是对分析区域的回溯性选择。该项目开发、测试和实施了一个综合多信号程序，综合不同的地震观测，可用于估计大地震的临近时间。所开发的工具和结果可以对了解地震活动和分析活动构造环境中的地震灾害产生重大影响。这项研究可以为更多关于地震物理和地震危险的观测、实验和理论研究提供信息并产生影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.