Velocity, moving direction and spreading boundary of mass-movement are important factors for prevention and reduction planning of landslide disaster. Without surveying, there are no means to measure these factors. However, no field surveying is available when ground destruction by the landslide is violent and dangerous. To such a landslide suddenly occurred at Hirose district in the north-western part of Nagano city, photogrammetry was examined by flights on October 5-th and 10-th in 1989. Landslide behaviour was analyzed by finding three-dimensional displacements of tracing points on photographs taken by the two flights. Accuracy of the photogrammetry, error propagation to displacement vector of the tracing points, and landslide behaviour analysis by the vectors on projection planes were investigated. Applicability of the phtogrammetry to the analysis of sudden and violent landslide behaviour was demonstrated by these investigations.
In this paper, principal component analysis is applied to multitemporal global normalized vegetation index (NVI) data for extracting combined vegetation features which are uncorrelated combinations of multitemporal global NVI data. The monthly NVI data are prepared by selecting maximum value in pixels of weekly NVI data for removing cloud effect. The averaged monthly NVI data are made by averaging monthly NVI data through 3 years (82.4-85.3), and are used for principal component analysis. As the result, 7 components from PC1 to PC7 are extracted, and the meanings of these 7 principal components are also discussed.
Lineaments in the SAR image are classified into 5 systems according to their orientations, landform and density of distribution in Gifu prefecture. Field survey is carried out for three out of these five lineament systems, and it is found that two kinds of the systems are strongly related to fault and the other one is strongly related to joint.
Hydrographic Department of Japan conducted seasur face gravity and magnetic survey of Tatibana Bay in June, 1991 to elucidate seabottom structure in relation with volcanic eruption of Unzen volcano. Precise gravity and magnetic anomaly maps of Tatibana Bay show a caldera structure and an intrusive voccanic activity related with caldera formation. Horizontal distribution of shallow seismic epicenters are in good agreement with local magnetic anomaly zone, which may indicate a intrusive volcanic activity are still in active below Tatibana Bay.