Comparison of InSAR capability for land subsidence detection between C-band and L-band SAR

Abstract

Investigates the capability of interferometric SAR (InSAR) using C-band (ERS) and L-band (JERS-1) SAR data for land subsidence detection in urban and rural areas. The Kanto Plains and the Saga Plains were selected as the test site. In the Kanto Plains, several continuous land subsidence areas are found both in urban and rural areas, while in the Saga Plains, they are located only in rural areas. We used several data pairs with different time intervals from two to five years from ERS and JERS-1 SAR data, in which observation periods nearly correspond with each other. The land deformation patterns were compared with each other in the data pairs of corresponding observation periods. In the Kanto Plains, the subsidence amounts in urban areas detected by JERS-1 were smaller than those detected by ERS, which might be due to the difference of minimum detectable subsidence. However, JERS-1 could detect major subsidence areas in rural areas, while ERS could hardly detect them. In the Saga Plains, ERS could not detect any subsidence in rural areas, while JERS-1 succeeded in detecting a significant one even by using the data pair with a five-year interval. These results verify that L-band InSAR will be a practical tool for land subsidence monitoring of the Japanese Islands, especially by using ALOS/PALSAR to be launched by Japan in 2004.