Exciting news! We're transitioning to the Statewide California Earthquake Center. Our new website is under construction, but we'll continue using this website for SCEC business in the meantime. We're also archiving the Southern Center site to preserve its rich history. A new and improved platform is coming soon!

Space-Time Monitoring of Groundwater in the Coastal Los Angeles Basins via Seismic Interferometry

Shujuan Mao, Albanne Lecointre, Robert D. van der Hilst, & Michel Campillo

Published August 16, 2021, SCEC Contribution #11578, 2021 SCEC Annual Meeting Poster #234

Relative changes in seismic velocity (Δv/v) are associated with perturbations in mechanical properties of crustal materials. Interferometry of ambient noise enables the continuous monitoring of relative changes in seismic velocity (Δv/v), which have been used to study various time-evolving processes in the crust. Here we extend the applications of Δv/v monitoring by not only detecting the temporal changes but also imaging the spatial variations, based on newly-developed coda-wave sensitivity kernels. We use the space-time observations of Δv/v to investigate the hydrologic processes in the Coastal Los Angeles Basins during 2000-2020. Seasonal variability of Δv/v, related to the annual recharge and withdrawal of groundwater, appears most pronounced in confined zones. Cumulative Δv/v, indicating a long-term groundwater decline, extend to broader areas including the unconfined forebay. The spatial patterns of Δv/v agree with surface deformation inferred from InSAR, but also further enable the characterization of aquifers and their hydrology at different depths. This pilot application shows the promise of using Δv/v observations to propel the knowledge about the temporal behavior as well as spatial variations of aquifer systems. Integrated with other geophysical data, the new insight obtained from Δv/v via seismic interferometry allows a more comprehensive description and understanding of near-surface hydrologic processes.

Key Words
space-time monitoring, hydrologic process

Mao, S., Lecointre, A., van der Hilst, R. D., & Campillo, M. (2021, 08). Space-Time Monitoring of Groundwater in the Coastal Los Angeles Basins via Seismic Interferometry. Poster Presentation at 2021 SCEC Annual Meeting.

Related Projects & Working Groups