南部フォッサマグナ地域の浅層地殻の変形過程 : 特に,新生代末における富士川谷の非対称背斜の形成過程  [in Japanese] Deformation of the shallow seated crust in the south Fossa Magna : Formation of the non-symmetrical anticlines developed in the Fuji River Valley  [in Japanese]

Deformation of the shallow seated crust in the south Fossa Magnais discussed on the basis of the analitical study of the asymmetrical anticlines developed in the Fuji River Valley. General trend of the Honshu Arc is turned from NE-SW to NW-SE direction at the western part of the south Fossa Magna where the Miocene Fujikawa Group is developed. In this district, many asymmetrical anticlines and keel-liked synclines were formed, when the violent crustal movement occurred at latest Neogene era. One wing of the sea symmetrical anticlines is very long and the other is short. Thickness of the strata forming the limbs of these anticlines changes abruptly from one wing to the other. This is due to the differencial vertical block faulting of the pre-Miocene basement in the course of sedimentation of the Fujikawa Group. Both limbs were steeply inclined after this synsedimentary tectonic movement happened. It is thought that increase of inclination of limbs was generated due to the reversed vertical block faulting at latest Pliocene age. The seismological and gravitational data, show that the basement blocks mentioned above has preserved at present in the shallow seated crust of the south Fossa Magna.