HR: 1340h
AN: S23A-0226    [Abstracts]
TI: Earthquake Damage Assessment using SAR Coherence
AU: * Atwood, D
EM: datwood@asf.alaska.edu
AF: Alaska Satellite Facility, University of Alaska Fairbanks, PO Box 757320, Fairbanks, A 99775-7320 United States
AU: Rathje, E
EM: e.rathje@mail.utexas.edu
AF: University of Texas at Austin, Dept. of Civil, Architectural, and Environmental Engineering, 1 University Station C1792, Austin, TX 78712 United States
AU: Guritz, R
EM: rguritz@asf.alaska.edu
AF: Alaska Satellite Facility, University of Alaska Fairbanks, PO Box 757320, Fairbanks, A 99775-7320 United States
AB: Damage assessment after natural disasters is critical to successful relief efforts, determining financial impact, and subsequent redevelopment. Earlier research has confirmed the utility of high resolution, optical satellite imagery for characterizing earthquake damage patterns in urban settings. Although effective, this approach is limited to daytime passes and cloud-free skies. Moreover, the presence of time variable shadows, seasonal variations in vegetation, and various anthropogenic changes poses technical challenges to differentiating earthquake damage. In contrast, Synthetic Aperture Radar (SAR) offers several advantages over optical data including day/night and all-weather imaging capability; as well as providing both amplitude and phase information. In this paper, the authors investigate the potential of SAR satellites (ERS-2 and Radarsat-1) for change detection in urban settings. Three earthquake events will be considered: The 1999 Kocaeli (Izmit) earthquake in Turkey, the 2003 Bam earthquake in Iran, and the 2004 Niigata Chuetsu earthquake in Japan. Repeat pass SAR observations provide the opportunity to apply interferometric methods, including the detection of differential motion and phase de-correlation. Temporal de-correlation is normally minimal in urban areas because of the large number of permanent scatterers. Structures that are unaffected by the earthquake should offer high correlation, whereas regions with extensive damage are expected to have significant de-correlation. We will explore the utility of using coherence loss as a means for classifying earthquake damage. The validity of the technique will be confirmed by analyzing the coincidence of coherence loss with known regions of damage, assessed from field surveys and optical satellite data. Based on our analysis, we will make recommendations regarding acquisition strategies that can be applied in future SAR missions.
DE: 0742 Avalanches
DE: 0933 Remote sensing
DE: 1217 Time variable gravity (7223, 7230)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 1294 Instruments and techniques
SC: Seismology [S]
MN: Fall Meeting 2005