HR: 1340h
AN: NG33C-0191    [Abstracts]
TI: Results From a Model-Independent Method of Monitoring a Geodetic Network for Patterns of Transient Deformation
AU: * Hurst, K J
EM: ken.hurst@jpl.nasa.gov
AF: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Granat, R A
EM: robert.a.granat@jpl.nasa.gov
AF: Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB: We have implemented two multi-station detectors for transient crustal deformation within the Southern California Integrated GPS Network (SCIGN). One of the primary goals of SCIGN is to detect transient deformation associated with the earthquake cycle in Southern California. Our methods are capable of monitoring SCIGN data for motions that would be too subtle to be detectable with data from just a single station. These methods are independent of the deformation mechanism and can be used to monitor a network to highlight areas of deformation for further study. For both methods we first remove linear and periodic signals from the data. The first method stacks the displacement magnitudes for stations within a given radius of a each grid point, creating a map of areas with stations experiencing simultaneous motion. The analysis is repeated for a suite of radii ranging from 20 km to 160 km. The second method uses a Hidden Markov Model (HMM) to identify mode changes within a time series. Times of coincident mode changes at multiple stations indicate regional deformation activity that may be sub-noise level. The regularized deterministic annealing expectation maximization algorithm is used to perform robust HMM fitting in the absence of a priori information about the source system. We present interesting examples of transient deformation signals gleaned from the SCIGN data during the period 1995-2005.
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005