Collaborative Research: Evolution of elastic wave properties during the seismic cycle: Experiments on dry and fluid pressurized meter-scale faults

Utah State University, Logan UT

Investigators

Abstract

The proposed research aims to illuminate the processes associated with earthquake precursors, crucial for improving seismic hazard forecasting. Earthquakes pose a significant threat to society. Despite decades of research, reliable precursors, indicative of imminent seismic events, remain elusive even though such precursors are routinely documented on small laboratory faults. The project focuses on meter-scale faults, offering a more realistic representation of natural fault systems. By adapting seismic interrogation techniques to meter-scale deformation experiments, the study strives to bridge the gap between centimeter-scale observations and real-world earthquake behavior. The outcomes of this work could have a significant impact on earthquake forecasting and mitigating the impact of seismic hazards. Moreover, the collaborative nature of this project promotes mentorship of an early-career PI and multiple graduate students, fostering the next generation of geoscientists. The project will use active source seismic interrogation techniques to study the mechanics of pre- and post-seismic deformation on dry and fluid saturated meter-scale faults. The goals of this project are to (a) explore whether robust variations in seismic wave properties can be identified before and/or after earthquakes, (b) the physical mechanisms responsible for such variations, and (c) to assess the potential for operational forecasting of ruptures on meter-scale faults, employing machine learning to analyze the data. While centimeter-scale experiments have provided valuable insights, their applicability to natural earthquakes involving complexities including fluids and spatially variable slip and stress changes remains uncertain. The project aims to fill this gap by conducting rupture experiments on a larger scale, studying the systematics of pre- and post-seismic deformation to identify earthquake precursors and their underlying mechanisms. The use of deformable meter-scale faults offering a more realistic representation of complexities inherent to natural fault systems, and arrays of strain, slip, and seismic sensors will help quantify the spatio-temporal variations of these complexities. The results of this work will be used to develop new methods for detecting and understanding earthquake precursors, which could lead to improved earthquake forecasting and reduced 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.