After the 1984 Western Nagano Earthquake (M=6.8), the airborne surveys on gamma ray and thermal infrared radiation were carried out with a helicopter in the southern Ontake area. The purposes of the survey are to catch the behaviors of bed gases (radon and thoron) around the epicentre and in the collapsed area and to clarify the mechanism of debris avalanche flow from the collapsed area. From the airborne research, the following relations were confirmed. (1) In the epicentre area, a great quantity of thoron radiates (thoron/potassium and thoron/radon were mor than 0.20 and 0.60, respectively) . (2) In the collapsed area, a high degree of thoron-radiation is counted (thoron/radon was more than 0.50) . (3) In the spacious collapsed area, the non-volcanic fissures are distributed densely, and forming of their fissures in this area triggered the spacious collapse (thoron/radon was 0.507) . (4) In Denj ogawa area, there are the network ground water veins here and there. The ground water smashed out from these veins pushed up the debris flows and flowed down them.
Two types of Laplacian Edge enhancement processing were applied on three different surface characters, Rock exposed, Mountainous vegetated, and Flat vegetated, of LANDSAT TM data to clarify several relations between data processing parameters and surface characteristics. As a result, several interesting features were confirmed on the trend of extracted lineaments, (1) Vertical and horizontal Edge enhancement was the best way to exrtact lineaments for every type of areas. Length and the numbers of these extracted lineaments were relatively short and large. (2) Omni-directional Edge enhancement generally gives too much enhancement, and mostly long and less Lineaments were extracted by the reduction of the topographic features.
To make the accurate retrieval of the statistically meaningful proportion of each category among MIXEL's, a category decomposition method based on maximum likelihood estimation is proposed. In this method, the observed multispectral vector is considered as a probability variable along with the approximation that each pure pixel value is characterized by normal distribution. The results show that this method can retrieve more accurate proportion than previous method. And 2 indices that estimate the degree of error are proposed. The first one is always available to show the degree of estimation error in each category, and the second one is not always available to estimate the degree of estimation error of each MIXEL.