Abstract
Soil liquefaction induces severe damage to infrastructure, buildings and residential houses. It is important to detect liquefaction area for planning of recovery scheme or future liquefaction prediction. However, wide range of the occurrence of soil liquefaction or liquefaction at restricted area sometimes prevents us to map all of a damaged area due to earthquake. Recently, as new analyzed techniques to detect damaged areas, the use of synthetic aperture radar (SAR) images has been proposed. Interferometric correlation analysis is one of the most effective methods especially to detect damaged area due to earthquake. This technique makes use of the difference of correlations calculated from SAR datasets acquired at co-seismic and pre-seismic period. Although the effectiveness of this technique has been shown previously, there is a disadvantage of its application to areas where scattering characteristics is rather variable (e.g., sub-urban and rural area). To discriminate liquefaction area by using correlation change, we have proposed an improved correlation analysis to use multi-temporal SAR images acquired before an earthquake and successfully detected liquefaction area at Kanto district due to the 2011 Tohoku earthquake. In this paper, we show the application results of newly-developed technique to the 2011 Tohoku earthquake as well as the 2011 Christchurch earthquake.
