HR: 1330h
AN: S52C-0157    [PDF]
TI: InSAR Seismic Wave Imaging In Real Time: Inversion Theory
AU: * Fatland, D R
EM: fatland@vexcel.com
AF: Vexcel Corporation, 4909 Nautilus Ct, Boulder, CO 80301-3242 United States
AU: Fitzgerrell, A
EM: alan@vexcel.com
AF: Vexcel Corporation, 4909 Nautilus Ct, Boulder, CO 80301-3242 United States
AU: Orrey, J
EM: Jeff.Orrey@vexcel.com
AF: Vexcel Corporation, 4909 Nautilus Ct, Boulder, CO 80301-3242 United States
AB: Synthetic Aperture Radar (SAR) can detect surface deformation resulting from seismic events by phase comparison (SAR interferometry or InSAR) of two images acquired before and after the event. We present here theoretical analysis of the application of InSAR to imaging seismic surface waves as they propagate, that is, where one of the two image acquisitions occurs in 'real time' during an earthquake. (This notion was brought to our notice by Dr. Paul Vincent of Lawrence Livermore National Laboratory.) The full problem is that of inverting an InSAR image of a surface-propagating earthquake to a characterization of the source seismic event. We consider the seismicity and the SAR to comprise a coupled system which produces an output as a function of both ground motion and imaging parameters; a system which only under some circumstances behaves linearly. The important recent accomplishments in this analysis are twofold: First, derivation of interferometric phase as a function of seismic and SAR parameters, and second the characterization of the system impulse response. This latter is expressed as output in response to a spike-wave propagating at seismic speed across flat terrain as it is swept by a SAR antenna beam. These results give us considerable insight into the non-linear aspects of the system behavior and more generally permit us to invert interferometric phase to seismic motion, to the extent that this is possible. A second inversion from seismic motion to source event characteristics--yet to be completed--will complete the solution to the full inversion problem. We present here theoretical results, model anlaysis, and remarks on practical implementation of a seismic imaging system.
UR: http://www.vexcel.com
DE: 0933 Remote sensing
DE: 7215 Earthquake parameters
DE: 7219 Nuclear explosion seismology
DE: 7255 Surface waves and free oscillations
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2003 Fall Meeting