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Radioscience Seminars

EE 350 Radioscience Seminar
Professor Howard Zebker
Autumn 2003-2004

Date: Wednesday, October 1, 2003
Time: 4:15 PM – Refreshments at 4:00
Location: Bldg. TC SEQ, Room 101

4-D imaging of the Earth's subsurface using InSAR:  Moving beyond the single interferogram
Prof. Howard Zebker
EE and Geophysics, Stanford University

Interferometric synthetic aperture radar (InSAR) techniques are perhaps the most exciting advance in geodesy in the past decade. The ability to map surface deformation at fine resolution over wide areas has led to many new insights into geophysical processes. Most studies to date have resulted from analysis of a single radar interferogram, and permit identification of subsurface phenomena such as fault slip, magma chamber inflation, or dynamics of the polar ice sheets. The ready availability of multiple data sets, as afforded by ERS or other spaceborne sensors, coupled with the decrease in computational and data storage costs, now allows analysis of time series data the examination of how deformation patterns change with time. These 4-D images present much more information about how processes at depth evolve and are more predictive about future events, an important capability for observing natural hazards such as earthquakes and volcanic activity. Special filters may be devised to discriminate steadily changing deformation patterns from those that are more episodic in nature. We review here results from several techniques based on temporal analysis of interferograms, including faulting on active volcanoes, pore fluid migration due to changes in seismic stress, hydrologic aquifer analysis, and permanent scatterer analysis of tectonic deformation.