Optimal GNSS observations in Southern California

Eileen L. Evans, & Sarah E. Minson

Published August 14, 2018, SCEC Contribution #8503, 2018 SCEC Annual Meeting Poster #131

We evaluate the current Global Navigation Satellite Systems (GNSS) observation network in southern California to 1) quantify the relative information provided by expanding the network to include seafloor observations, and 2) to identify optimal locations for future GNSS observations. These goals require considering potential locations both onshore and offshore, while considering multiple scientific objectives: optimal locations for observing an earthquake rupture (requiring observations within 1-3 locking depths of active faults) will differ from optimal locations for estimating long-term fault slip rates (which may require observations farther away). Furthermore, the high cost of seafloor geodesy limits the number of stations that may be deployed and monitored offshore. Therefore, it is essential that additional onshore and/or offshore stations are selected and positioned in such a way to provide the most informative data for resolving fault slip rates. To identify optimal locations for future geodetic observations, we use the theory of information entropy, a measure of the amount of missing information about parameters whose values are uncertain. In the case of southern California interseismic deformation, the primary uncertain parameters are fault slip rates and tectonic block motions within a kinematic block model. In the case of coseismic deformation, the uncertain parameters are fault slip. Ultimately relative financial costs of seafloor geodetic technology may be compared in terms of information gain per dollar, and will enable well-informed decisions about expanding current geodetic networks, both onshore and off.

Key Words
GPS, GNSS, Block Model, interseismic, coseismic

Citation
Evans, E. L., & Minson, S. E. (2018, 08). Optimal GNSS observations in Southern California. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy