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

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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.