Abstract
Distribution of lineaments from the Landsat images around the Aso caldera shows good agreement with that of active faults which were found by geological investigations and photointerpretations. These active faults cut the Aso volcanic ash beds and sometimes the Akahoya ash bed which is the key bed indicating the age of about 6, 000 Y.B.P..
The lineaments elongated in ENE direction at southwest and northeast sides of the caldera correspond with the active faults which suggest the presence of the fracture zone that run under the caldera center.
Macroscopic investigations of the image also show the distribution of major lineaments which are elongated in NNW, NW and NE directions respectively, and are 20-30 km long in the basement rocks found in surrounding areas of the caldera. These lineaments seem to reflect the presence of young faults resulted from the tectonic movement since the Pliocene.
