Using Differential SAR Interferometry to Detect the Land Subsidence in the Pingtung Area
Date Issued
2004
Date
2004
Author(s)
Nien, Pei-Fen
DOI
zh-TW
Abstract
Abstract
Southwestern Taiwan is located in the transition zone between subduction to the south and collision to the north. The rapid subsidence of the Pingtung Plain, especially near the coast, has caused many land-use problem.
InSAR (SAR Interferometry) is a geodetic tool now widely applied in earth surface deformation, which has the benefits of its high spatial resolution and centimetric accuracy. D-InSAR (Differential SAR Interferometry ) aims at the measurement of ground deformation using repeat-pass interferometry. We apply D-InSAR geodetic technique between 1995 and 2000 for land subsidence in the Pingtung Plain and perform the two-pass method by using an external DEM (Digital Elevation Model), in which we can subtract from the interferogram that is converted into DEM coordinates. We construct a differential interferogram using the DIAPASON software based on two SAR images from ERS-1 and/or ERS-2 satellites.
The result of D-InSAR reveals that the critical subsidence region was located near the mouth of Linbien River. The analysis of D-InSAR result shows the fringe is obvious when the groundwater level is lowest during one year. The subsidence rate is about 2.9 cm/month in the dry season from January 31 to May 16, 1996. The subsidence rate decrease to about 0.57 cm/month form 2.9 cm/month in the dry season from 1995~1999. However, in the wet season , the subsidence rate is about 0.11~0.55 cm/month shown by 4 D-InSAR pairs.
Our 4-month duration (January ~May) D-InSAR pattern is highly consistent with the isopach of fine-grained sediment thickness of core data from the Groundwater Monitoring Network Plan in Pingtung Plain (Huang, et. al., 1998) that the compaction of fine-grained sediments and the overdraft of groundwater play important roles of observed subsidence.
Subjects
地層下陷
合成孔徑雷達
合成孔徑雷達差分干涉技術
D-InSAR
SAR
land subsidence
Type
thesis
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