Collaborative Research: Investigating Links Between Earthquake Swarms, Aseismic Processes, and Fault Zone Heterogeneity in Volcanic and Geothermal Areas

Earthquake swarms are complex clusters of seismic events that can significantly impact communities and infrastructure. They often occur in volcanic and geothermal areas and regions affected by human activities such as fluid injection or extraction. Identifying and understanding the factors that influence earthquake swarms is crucial for improving our ability to assess and mitigate seismic hazards. This research project aims to unravel the complex behavior of earthquake swarms by examining how they are affected by internal factors, such as the properties of the fault zones, and external factors, such as the slow fault and fluid movements. By studying major earthquake swarms in Hawaii and California, the research team will gain insights that can help improve earthquake forecasting and risk assessment. This project also provides training for graduate students, a postdoctoral researcher, and undergraduate students at two US institutions while fostering collaborations between scientists from the US and Japan. The research team will investigate earthquake swarms in volcanic and geothermal areas using a combination of seismic and geodetic data analysis and computational modeling. They will examine earthquake source characteristics, spatial and temporal clustering patterns, and slow deformation processes to understand the relationships between earthquake sequences, aseismic slip, fluids, and fault zone properties. High-resolution data from well-instrumented areas will be used to characterize multi-scale faulting processes during major swarms. The team will develop physical models of fault zones based on laboratory friction laws and heterogeneous stability and strength conditions. These models will simulate the interplay between seismic and aseismic slip, fluid diffusion, and stress transfer, enabling realistic representations of fault behavior during swarms. By integrating observations with these models, the project will advance our understanding of why earthquake swarms start, grow, and decay and what they reveal about underlying fault zone conditions. 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.