In order to detect the damaged areas, urgent observations were
performed by the ALOS/PALSAR in several different modes. A data in
fully polarimetric mode was acquired on April 8, 2011, about one
month after the earthquake and tsunami disaster. Two other polarimetric
PALSAR images, acquired at the study site before the 2011
Tohoku earthquake, were also used to evaluate changes in polarimetric
signatures, as summarized in Table 1. All datasets used in the study
have the same acquisition parameters with the same viewing configuration.
Consequently, we can assume that differences in the images
are directly related to the changes that occurred to the ground
scatterers.