SCEC Award Number 22015 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title COSI-Corr+, An open source code for 2-D and 3-D measurement of ground deformation from optical image correlation
Investigator(s)
Name Organization
Jean-Philippe Avouac California Institute of Technology
Other Participants Aati, Saif
SCEC Priorities 2c, 2d, 2e SCEC Groups Geology, Geodesy
Report Due Date 03/15/2023 Date Report Submitted 11/14/2024
Project Abstract
 The project supported the development of an open-source software to measure precisely 2-D and 3D measurements of ground deformation caused by earthquakes by utilizing optical image correlation. The use of high-resolution satellite imagery allows us to measure Earth’s surface deformation due to earthquakes. These measurements can be used to and determine surface ruptures, slip distribution, and off-fault strain. This data provides insight into earthquake mechanics and provides constraints for probabilistic fault displacement hazard assessment. The methodology consists of an optimized geometric modeling process for high-resolution optical imagery from several satellites and adding factors such as satellite jitter and image alignment. The COSI-Corr+ software, coupled with Docker for compatibility across operating systems, allows for sub-pixel accuracy and 3-D displacement measurement. Results from the project have shown the efficiency of the software in obtaining accurate 3-D displacement fields, as seen in the 2019 Ridgecrest earthquake. The method has now been applied to a number of other earthquakes.
Intellectual Merit The COSI-Corr+ project has contributed to SCEC's intellectual merit by providing open-source software to measure ground deformation. Measuring co-seismic deformation has advanced our understanding of earthquake sources by providing constraints on co-seismic slip distribution. These measurements have been used to constrain the evolution of fault friction during seismic slip which is a central piece of physics needed to develop dynamic models of the earthquake cycle.
Broader Impacts The project has contributed to the broader impacts of SCEC by promoting educational opportunities, fostering mentoring and training at Caltech, encouraging cross-collaboration within the SCEC community, and reaching out to educate our local communities. By incorporating students from diverse backgrounds, including underrepresented groups, we have engaged students by offering outreach and training opportunities in geoscience, which benefits their academic and professional growth. Additionally, the project has strengthened research infrastructure through enhanced data-sharing networks and collaborators and provided valuable societal benefits by advancing efforts in earthquake preparedness.
Exemplary Figure Figure 2: Co-seismic slip distributions of 20 events with magnitude larger than 6.4, measured from co-registration and correlation of satellite optical images (Milliner, Aati and Avouac, 2024).
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