三浦半島引橋断層および北武断層の第四紀後半における変位〔英文〕
スポンサーリンク
概要
- 論文の詳細を見る
As a result of field mapping and aerial photograph and map interpretation, maps and tables of late Quaternary displacements at the Hikihashi and Kitatake Faults are presented. Both faults, exhibiting clear topographic displacements, are Certainty I features according to the classification of MATSUDA et al. (1977).The Hikihashi Fault, upthrown to the south, is interpreted as dominantly right-lateral, with thrusting in the east (fault strike 100°east of north) and graben development in the west (fault strike 120°). The Kitatake Fault, upthrown to the north-east, is dominantly right-lateral, with a probable thrust component.Tabulated data show the Hikihashi Fault has an average horizontal displacement rate of at least 2m per 1, 000 years and vertical displacement rate of about 0.5m per 1, 000 years. The Kitatake Fault has an average horizontal displacement rate of more than 3m per 1, 000 years and vertical displacement rate of more than 0.4m per 1, 000 years. Both faults, using Matsuda's 1977 classification, are thus Class A active faults, with net slip rates of greater than 1m per 1, 000 years. Ratios of horizontal to vertical displacement allow calculation of the principal shortening direction as about 161°(or 341°) east of north.A comparison of recorded seismicity in Miura Peninsula with estimated recurrence intervals for transcurrent faults suggests there could be movement at an active fault in the peninsula within a few hundred years.
- 日本第四紀学会の論文