Probing the mechanical properties of the crust and upper mantle using geodetic, remote sensing and seismological observations

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The Accomplishments Based Renewal will shed light on the laws that govern continental deformation and the seismic cycle, such as the processes of strain release during large earthquakes and the slow strain build up between successive earthquakes. This topic is of broad interest in geology and the result of the research could significantly advance methods for seismic hazard assessment. These are questions that the recent National Academies of Science, Engineering and Medicine report Earth in Time note as grand challenge questions in the Earth sciences. The researchers will analyze and model high precision GPS measurements of ground deformation before, during and after large earthquakes in California and Tibet using novel methods developed by the lead researcher. The project will support educational and outreach activities by the PI to train students and postdoctoral researcher involved in the project. The project will foster international scientific collaboration.The objective of this project is to advance the knowledge of crustal and upper mantle rheology and to improve the quantitative understanding of how seismicity relates to geodetic strain. The researchers will analyze High-Rate GNSS measurements of postseismic deformation and aseismic transients using a new methodology based on an Independent Component Analysis technique. They will compare the geodetic and seismicity observations with model predictions to constrain the friction properties governing the earthquake nucleation process and aseismic slip, and the viscosity structure. They will analyze data from California, related to the 2019, Mw7.1 Ridgecrest earthquake and the 2020 Westmorland swarm in particular, and data related to the Mw 7.4, 2021a Madoi earthquake in Tibet.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.