Analysis of surface deformation based on PS-InSAR technique: Case studies in coastal plain, SW Taiwan
Date Issued
2008
Date
2008
Author(s)
Tung, Hsin
Abstract
Differential Interferometric Synthetic Aperture Radar (DInSAR) technique has increasingly been applied in geosciences as a powerful tool to monitor land surface deformation. In addition, the large archives of SAR data enable us to monitor ground deformation continually. However, temporal and spatial decorrelations of radar signal have prevented this technique from more frequent utilization. An advanced InSAR processing technique that tracks the signals of discreted point-wise targets called Persistent Scatterers Interferometry Technique (PSInSAR) was herein applied to our research area in order to better understand the deformation patterns. Thus the PSInSAR method allows us to know the deformation of these discrete points that were minimally affected by decorrelation of radar signals through time.he active orogeny of Taiwan generated large amount of surface deformation that were partitioned throughout the island, which provides a great opportunity for analyzing tectonic displacements through interferometric methods. Here we present a PS-InSAR result deduced from 1996-1999 time spans in and around Tainan Tableland of southwestern Taiwan close to the deformation front. About 1,650 persistent scatterers are deduced from the processing of 33 SAR images (Tract: 232, frame, 3141) in an area of 144 km2. The maximum slant range displacement (SRD) rate along the radar line of sight (LOS) toward to satellite is about 8 mm which is close to the borehole data after transferring SRD rate to vertical deformation rate. Besides, the nonlinear deformation evolutions show a respectable correlation with seasonal rainfall on the Tainan Tableland near the Houchiali fault. One of the reasons might be the behaviors of fault creeping during the rainy seasons. These results indicate that the Tainan Tableland is an aseismic area.n addition, anthropogenic ground subsidence due to massive pumping of groundwater is one of problems in Taiwan. The Yunlin County located in the southwestern coastal region of Taiwan is one of the most counties with serious land subsidence because of the agricultural needs. Here, we also represented a both stacking DInSAR and PSInSAR results deduced from 1996-1999 time spans for monitoring of land subsidence in this area. Both DInSAR and PSInSAR results show the Baojhou, Tuku Township and northern Mailiao reveal a maximum subsidence rate of about 6 cm/yr along LOS and the Taishi Township located on the coastal area reveals a subsidence rate of 1.58 cm/yr, which is quite coincident with precise leveling result. These two results have proven that the effective reduction of labor and cost could be achieved by using this technique on monitoring land subsidence in Yunlin County.
Subjects
InSAR
DInSAR
PSInSAR
Tainan Tableland
Houchiali Fault
Tawan Lowland
Yunlin County
Surface Deformation
Land Subsidence
Type
thesis
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