SCEC Award Number 17042 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Assembly of the Community Geodetic Model and GPS Survey of the Imperial and Cerro Prieto Faults
Investigator(s)
Name Organization
David Sandwell University of California, San Diego Alejandro Gonzalez-Ortega University of California, San Diego Jose Javier Gonzàlez-Garcìa Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico) Wayne Thatcher United States Geological Survey
Other Participants Xiaohua Xu
SCEC Priorities 1a, 2a, 1c SCEC Groups Geodesy, CXM, SAFS
Report Due Date 06/15/2018 Date Report Submitted 08/14/2018
Project Abstract
 Our investigation has two components. The first is the assembly of the community geodetic model (CGM). The main activity was to work with the community to further develop a time-dependent geodetic model at 500 spatial resolution. We hosted a workshop at Scripps on March 12 and 13. The full report can be found at the CGM web page http://topex.ucsd.edu/CGM/CGM_html/ . The second aspect of our research is to perform and analyze campaign GPS measurements of the Imperial and Cerro Prieto Faults in northern Baja California, MX. In February 2018 Researchers at SIO and CICECE performed a campaign GPS survey of 38 monuments across the Cerro Prieto and Indiviso Faults. These data are being combined with Sentinel-1 InSAR measurements to estimate the moment accumulation rate along these major faults [Gonzalez-Ortega et al., 2018]. Preliminary GPS velocity field for extended CC and DD monuments starts to delineate the velocity gradients across Indiviso and Tulecheck faults. More surveys are needed in order to have better constrains for this velocity gradient.
Intellectual Merit Two of the top priorities of SCEC5 are (1) to better understand how faults are loaded across temporal and spatial scales and (2) to establish the role of off-fault inelastic deformation on strain accumulation, dynamic rupture, and radiated seismic energy. Surface crustal velocities and deformation time series are one of the key boundary conditions needed for addressing these problems. The quality and quantity of GPS and InSAR data are increasing rapidly and many groups are developing detailed crustal deformation models as part of the SCEC Community Geodetic Model (CGM). The overall objectives of the SCEC CGM are to develop a high spatial resolution (200-500 m) crustal motion model consisting of velocities and time series for Southern California that leverage the complementary nature of GPS and InSAR observations. Reprocessing of long GPS time series has provided high accuracy vertical measurements that reveal a wide range of new hydrologic and tectonic signals. In addition, two new C-band InSAR satellites (Sentinel-1A and B) are providing highly accurate systematic coverage of the entire SCEC region every 12 days from two look directions.

Our proposal has two main components. The first part is to continue the assembly of the SCEC CGM. This involves developing consensus models from a suite of published models, urging the community to work toward consensus models, and upgrading the components of the CGM as new GPS and InSAR data become available. The second part of our proposed investigation is to continue a campaign GPS and InSAR analysis of the Imperial, Cerro Prieto and nearby faults in the Mexicali region of northern Baja California, MX. This is a collaborative effort between scientists at CICESE and SIO. Over this past year we have made significant progress in both as described in our progress report.
Broader Impacts Each year Yuri Fialko and I teach a course at UCSD called Space Geodesywhere we train the students in processing and interpretation of GPS and InSAR data. In addition, we have several field trips to collect GPS data in Northern Baja MX as well as in the Salton Trough area. The Mexico field work is done in collaboration with students and faculty at CICESE in Ensenada, MX. These these field trips, and the international collaboration, broaden the educational experience of students on both sides of the border..
Exemplary Figure Figure 3: Preliminary GPS velocity in northern Baja California in ITRF2008. Black arrows are continuous GPS data. Blue arrows are GPS survey mode data, and green dots represents new sites recently survey during this time project.