抄録
Green-tuff Region is defined as existence of abundant submarine volcanic rocks of Early Miocene and overlying oil-bearing pelitic clastic sediments of Late Miocene-Pliocene age. The region is also characterized by predominant distribution of landslide phenomena in the outcropping area of pelitic sediments. The region has been folded and faulted since Late Plocene age, moreover hilly and mountainous area is considered to be uplifting recently.
From paleotemperature analysis by authigenetic minerals and studies of the relation between porosity and burial depth, amounts of uplifting movements are estimated, and it is clarified that overlying Pliocene sediments has been eroded out throughout the Quaternary age, and severe fracturing occurred in the Neogene sediments. This caused the action of groundwater that accerelate landslide phenomena in the Green-tuff Region.
