HR: 0800h
AN: G51C-0855    [Abstracts]
TI: 3D Deformation Fields From Existing InSAR Satellites
AU: * Bechor Ben Dov, N
EM: nbechor@stanford.edu
AF: Dept. of Geophysics, Mitchell Bldg. #360 Stanford University, Stanford, CA 94305-2115 United States
AU: Zebker, H
EM: zebker@stanford.edu
AF: Dept. of Geophysics, Mitchell Bldg. #360 Stanford University, Stanford, CA 94305-2115 United States
AU: Zebker, H
EM: zebker@stanford.edu
AF: Dept. of Electrical Engineering, Packard Bldg. #334 Stanford University, Stanford, CA 94305-9515 United States
AB: We present a method to obtain 3D deformation from currently operating InSAR satellites. Conventional InSAR processing provides information about the travel time only along the satellite line of sight, while geophysical processes are three-dimensional. For example, along the San Andreas fault system much of the deformation is often aligned nearly parallel to the satellite's flight direction (azimuth), and therefore cannot be readily observed with current processing schemes. A pair of ascending/descending interferograms, when available, adds information on a plane containing the two lines of sight and can be used to separate the travel time delays on that plane. This resolves mainly the vertical and range-direction components, with the delays along the satellite flight direction remaining unknown. At least three solutions have been proposed to obtain the 3rd dimension: (1) assume that the observed pattern is due to an expected largest principal direction of deformation, (2) use data from independent techniques such as GPS to obtain the true components in site locations and interpolate for the InSAR data, and (3) in cases of large deformation (~ 15 cm) the amplitude offsets between the two SAR images can be used to calculate the deformation component parallel to the satellite's flight direction. We propose a method based on the geometry of observation to obtain the along-track component, in which we view the surface from different angles. The projection of deformation on each line of sight is different for each direction, and their phase difference provides information on the along track component. We test our method using data from the Hector Mine earthquake, and compare the results to the known deformation pattern of that earthquake. In the our test case interferometric phase change of pi/2 implies a 3.3 m offset in the satellite flight direction. Mapping the phase difference yields an image of along-track motion.
UR: http://www.stanford.edu/~nbechor/InSAR3D
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1294 Instruments and techniques
DE: 1299 General or miscellaneous (1709)
SC: Geodesy [G]
MN: Fall Meeting 2005