抄録
Landslides were mapped by air-photograph interpretation in the main part of the Tohoku District in Northern Japan and characteristics of landslide distribution are discussed from geological point of view. The Tohoku District can be divided into two parts from geology and geomorphology and also from landslide distribution. The Kitakami Mountain area, the east part, underlain by hard rocks of Palaeozoic to Mesozoic Eras is rarely covered by landslides or landslide deposits. The Oh-u and Dewa Mountain areas, the west, underlain by the Lower Miocene marine volcanics called green tuff and the Upper Miocene to Pliocene clastic rocks are characterized by crowded and dense distribution of landslides in several scales. In detail, landslides medium to small in scale are more densely observed in the areas underlain by the Upper Miocene clastic rocks. Large and medium landslides are often observed in the area of “green tuff”, though the area has been believed to be barren in landslide distribution. It is considered that landsliding is one of main processes of erosion for the Neogene rocks in the Tohoku District. Gigantic or large landslides are often recognized on the slope of the Quaternary volcanoes. Those volcanoes have several extra conditions different from other geologic bodies.
