SCEC Award Number 20026 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Separation of tectonic, hydrological and anthropogenic sources of ground deformation in Southern California
Name Organization
Roland Bürgmann University of California, Berkeley Xie Hu University of California, Berkeley
Other Participants
SCEC Priorities 1a, 2a, 3f SCEC Groups Geodesy, SDOT, CXM
Report Due Date 03/15/2021 Date Report Submitted 03/10/2021
Project Abstract
The primary goal of this project is to provide explicit contemporary ground displacement products attributed to tectonic and both natural and anthropogenic non-tectonic sources in the SCEC region. Interseismic creep may localize along the fault or may distribute across a limited width about the fault while the surface deformation off the fault usually spreads out in a long-wavelength pattern. On the other hand, human activities such as groundwater pumping, hydrocarbon and geothermal activities may result in highly localized ground deformation. Temporally, hydrologically driven elastic/poroelastic displacements are believed to be generally correlated with the seasonal precipitation and water level changes. Here we rely on the existing CGM efforts of 2014-2018 Sentinel-1A/B InSAR results from Sandwell & Xu which incorporate GPS results generated by Zeng & Shen. We attempt to determine the presence of seasonal features and further quantify the peak-to-peak amplitude and phase using an efficient statistical strategy referring to the number of peaks and troughs in the first-order variations of time-series deformation. We obtained higher-level time-series products including the secular rates, seasonal amplitude and phase. The outstanding discontinuities and high-frequency signals in these maps reflect deformation due to various tectonic and non-tectonic features such as faults, the boundaries between basins and ranges, the hydrogeological heterogeneities contained in aquifer systems, and industrial production wells. This project helps better understand the coexisting tectonic and non-tectonic processes and their potential interaction across California, and also assists the earthquake hazard assessment and mitigation for the SCEC community, the public, and industry.
Intellectual Merit This project enhances the SCEC Community Geodetic Model (CGM) by systematically differentiating tectonic and non-tectonic sources and by characterizing their respective spatiotemporal behaviors over the entire SCEC region. It aligns with the CGM’s aim to integrate GPS and InSAR data sets for measuring secular motions, determining geodetically inferred fault slip rates, and to determine time-varying deformation signals associated with tectonic and non-tectonic deformation sources over the full range of length and timescales.
Broader Impacts This project supported the academic career development of a former postdoc Xie Hu at UC Berkeley to become a junior faculty member at the University of Houston during the project period. A research paper tied to this project is currently under internal review by coauthors. The Sentinel-1 InSAR secular rates and seasonal amplitude and phase values over the entire SCEC region derived from this study will be provided as the supplement associated with the publication. These products can support interdisciplinary research among geodesists, geologists, geophysicists, and hydrologists, and also support decision-making among engineers and urban planners.
Exemplary Figure Figure 2