Updating GNSS data in southern and central California

Rigoberto Rincon, Gareth J. Funning, & Karlee M. Rivera

Submitted September 8, 2024, SCEC Contribution #14034, 2024 SCEC Annual Meeting Poster #073

GNSS velocities are used by geophysicists to estimate the amount of elastic strain accumulating on faults, an important input into models of seismic hazard. While there is a large network of continuously operating GNSS stations in central and southern California, we can improve data coverage, and thus the resolution of our models based on GNSS data, by making additional survey measurements in places where there are data gaps. The extra data coverage will support efforts such as the Community Geodetic Model, facilitate earthquake response, and improve measurements of future coseismic and postseismic deformation.

We conducted a GNSS field campaign in central and southern California over eight weeks. We focused on three key areas: (i) Parkfield/Cholame, (ii) the Cajon Pass and Mojave segments of the San Andreas fault, and (iii) the Inland Empire and Coachella Valley. During this time, we surveyed 37 GNSS sites: 25 sites in southern California and 12 sites in Parkfield. Of these 37 sites surveyed, 12 were found and recovered by UCR for the first time, and 25 sites were resurveyed from previous campaigns. To identify potential GNSS sites to survey, we reviewed previous SCEC, NGS, USGS, and UCR campaigns to identify previously surveyed sites and utilized Google Earth to determine if they were accessible and recoverable. If a site was chosen and found, we surveyed and occupied it for ~12-24 hours. We produced Google Maps and Google Earth Pro maps of KML files of the GNSS sites surveyed in this study. The raw data we collected from the sites were converted to RINEX files, as a quality check the RINEX files will be processed using the NGS OPUS tool.

This GNSS campaign provides new and updated measurements to GNSS sites that should help to fill critical data gaps and refine geodetic observations before any potential earthquake happens. Ultimately, we hope it will improve the science return for a future event in the areas we surveyed.

Key Words
Updating GNSS, velocities, GNSS data, Community Geodetic Model, field campaign

Citation
Rincon, R., Funning, G. J., & Rivera, K. M. (2024, 09). Updating GNSS data in southern and central California. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy