HR: 16:15h
AN: G32C-02    [PDF]
TI: Expected Performance of the Proposed PBO Network From Numerical Simulations
AU: * Schmidt, D
EM: das@uoregon.edu
AF: University of Oregon, Geological Sciences, 1272 University of Oregon, Eugene, OR 97403-1272 United States
AU: Murray, J
EM: jrmurray@pangea.stanford.edu
AF: Stanford University, Mitchell Building Room 360, 397 Panama Mall, Stanford, CA 94305-2215 United States
AU: Segall, P
EM: segall@pangea.stanford.edu
AF: Stanford University, Mitchell Building Room 360, 397 Panama Mall, Stanford, CA 94305-2215 United States
AB: With the recent funding approval of EarthScope, the scientific community is poised to begin the installation phase of the proposed Plate Boundary Observatory (PBO). GPS and strainmeters will soon be distributed across the western United States in a manner designed to target specific scientific objectives. While a blueprint for the placement of stations is already established, there exists a window of opportunity prior to the installation of instruments where the network geometry can be optimized. We perform numerical simulations to evaluate the performance of the proposed network. Three characteristic events are simulated: an aseismic transient on the central San Andreas fault, a slow earthquake on the Cascadia subduction interface, and a dike injection at Mount St. Helens. Results for transient source models describe the PBO network performance as a function of the magnitude and duration of an event and provide insight into the expected level of resolution. For each simulation, synthetic GPS and strainmeter data are created that include white noise and a random walk components. The Extended Network Inversion Filter (ENIF) [{\it McGuire and Segall,} 2003] is used to infer the original source parameters from synthetic time series given the proposed station distribution. The ENIF is an implementation of a Kalman filter that is well suited to extract a time-dependent signal from noisy data and is efficient at analyzing large time series. Resolution of the source process is evaluated by comparing the synthetic input model with the inferred source model estimated by the filter. We find that the proposed PBO network at Parkfield is nearly optimal compared to a network composed of random station positions. A discernible variation in source resolvability along the San Andreas fault is attributed to the along-strike variation in station density. For Cascadia, the slow earthquakes recently observed from existing GPS data appear to be at the lower threshold of resolvability for the proposed PBO network, but within the detection threshold. We also find that the proposed network for Mount St. Helens is currently optimized for deep source events and shallow deformation events ($<$ 4 km in depth) are not well resolved.
DE: 1294 Instruments and techniques
DE: 3210 Modeling
DE: 6339 System design
DE: 8494 Instruments and techniques
SC: Geodesy [G]
MN: 2003 Fall Meeting