SCEC Award Number 20182 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Updating Campaign GPS Time Series for Integrated Community Geodetic Model
Investigator(s)
Name Organization
Zheng-Kang Shen University of California, Los Angeles
Other Participants
SCEC Priorities 1a, 2a, 3e SCEC Groups Geodesy, CXM, FARM
Report Due Date 03/15/2021 Date Report Submitted 03/25/2021
Project Abstract
 This project is to continue collecting all the campaign GPS data observed in southern California, and process/reprocess the data to produce the station position time series. The result will be combined with the continuous GPS and InSAR data to produce the joint crustal displacement time series for the SCEC CGM project. We have collected all the campaign GPS data from the UNAVCO and USGS data archives collected up to the end of 2019, and processed the data to produce the station position time series. We have also modeled the data to solve for site velocities and coseismic and postseismic displacements. The campaign GPS time series and the crustal motion solutions are deposited at the website http://scec.ess.ucla.edu/~zshen/cgm/cgm.html, to be freely accessed and used by the community.
In addition to working on updating the campaign GPS time series, this year we have also developed a 3-D GPS/InSAR integration algorithm and applied that to a compilation of GPS and InSAR data in southern California. In the algorithm discrete GPS data points were interpolated to obtain a 3-dimensional continuous velocity field, which was then combined with the InSAR line-of-sight (LOS) velocity data pixel by pixel using the least-squares method. This method has been applied to recover the 3-D deformation field in southern California, and produced some promising results, particularly for hydrologic activity related vertical deformation.
Intellectual Merit Production of the campaign GPS time series and development of the 3D GPS/InSAR integration method help to “develop a Community Geodetic Model (CGM) for use by the SCEC community in system-level analyses of earthquake processes over the full range of length and timescales”, and to “develop vector time series of crustal deformation at ~1 km spatial resolution and better than seasonal temporal resolution.”
We have developed innovative methods to adequately estimate and properly treat the GPS and InSAR data errors, which is the key to the success of optimal combination of the GPS and InSAR data.
Broader Impacts The project contributed to updating the computational facilities for GPS data processing and analysis.
Exemplary Figure Figure 2. Campaign GPS site velocities in southern California and its vicinities. Velocities are referenced to the North America frame.