Disaster monitoring from space

摘要

Remote sensing technology has been widely applied to disaster prevention management. It is the technology to observe the earth surface from satellites. This technology has two merits, to acquire wide two-dimensional information at a time, and to acquire the information periodically. Utilizing these merits, this technology can be used at each phase of disaster prevention management consisting of prevention planning, disaster warning, disaster monitoring, and evacuation and reconstruction after disaster. Remote sensing can provide invisible information in addition to acquire wide-view image data from space. Synthetic Aperture Radar (SAR) illuminates microwave to the earth from a satellite and collects the reflected echo from the surface. Interferometric processing of SAR data can detect the subtle movement of the surface. The information of the surface movement by SAR is useful to monitor the land deformation for the disaster prevention management complementing the existing leveling and GPS technique. PSInSAR (Permanent Scatters Interferometric SAR) is one of interferometric techniques to be applied to practical projects. In this paper, two sample projects are shown after the explanations of the PSInSAR principle. Tokai earthquake risk assessment is the first example. PSInSAR detects the land subsidence at Tokai district and gives the time history of the subsidence at Hamaoka. This result was compared with leveling results, and it can be used for the earthquake risk assessment. PSInSAR result along the Kakkonda River at Iwate prefecture is another example to show the capability of PSInSAR to detect the crustal movement along the active fault. These examples show the usefulness of remote sensing technology for disaster prevention management.