Landslide observation by ground-based SAR interferometry

Abstract

A ground-based synthetic aperture radar (GB-SAR) system was installed for the observation and monitoring of post-landslide slope in Kurihara-city, Miyagi, Japan. The system is operated at 17 GHz (Ku-band) with a frequency bandwidth of 150 MHz. Horn antennas scan about 2 m horizontally to cover a large observation area and SAR processing is applied to achieve higher azimuth and range resolutions. In addition, the interferometric technique is used to detect very small changes on the target, resulting in the expected interferometer resolution of 0.1 mm. In 2011, the system operated from November to December to acquire preliminary results and to study the feasibility of the technique for monitoring landslide surface. During the period, major events on the landslide surface did not happen and, thus, no significant changes were detected by the GB-SAR system. However, it detected small movements at some locations approaching to the system that is likely caused by a snowfall. It demonstrates the capability of the GB-SAR technique in detecting very small changes on a target.