立川断層とその第四紀後期の運動
スポンサーリンク
概要
- 論文の詳細を見る
The Musashino Upland, a dissected fan of the Tama River in the western suburbs of Tokyo, is displaced by the Tachikawa fault, which runs in a NW-SE direction with long-continued flexure scarps.Using the tephrochronological method and data of water well logs, the author investigated geomorphic features and movement history of the fault in detail. It is thus revealed that the fault has displaced the terrace surfaces of various ages, including the Tc3 surface of 14, 000 years B.P. and the Holocene old stream channels (Fig. 1, Fig. 10). The Plio-Pleistocene sediments, buried under the Musashino Upland, have been vertically displaced about 70m at Hakonegasaki (Fig. 5, Fig. 6). This fault has only vertical displacement with no strike-slip component, and the upthrown side of the fault is northest. The long-term average slip-rate, derived from the displacement of terrace surfaces, is the largest in the central part of the fault and gradually decreases toward the both ends. The maximum average slip-rate is 36cm/1000 years.The total length of the fault is 21km. If examined in detail, it may be divided into two segments from discontinuity of the geomorphic expression and difference in the long-term slip-rate (Fig. 11). No sign of fault movement has been found from precise levelling across this fault for 40 years. So it is thought that fault movements had been recurred on this fault with large earthquakes in the late Quaternary period. The fault displacement in an earthquake, the earthquake magnitude, and its recurrence interval are estimated at about 1.8m, M. 7.1, and 5, 000 years, respectively.There are two types of surface deformations along the Tachikawa fault. One is a flexure scarp of 100-300 meters in width (Fig. 8). This flexure scarp is thought to have been formed by the existence of thick unconsolidated fluvial gravel deposits overlying the faulted Plio-Pleistocene sediments. The other is a broad undulation of a few kilometers in a half-wave length across the fault trace (Fig. 12). This undulation seems to reflect the elastic dislocation of the crust due to the movements of the Tachikawa fault.
- 日本第四紀学会の論文
著者
関連論文
- 新富士火山初期の大きなソレアイトマグマだまりにおける結晶分化(火山のモデル(II))
- 愛媛県西条市における中央構造線岡村断層のトレンチ発掘調査
- 糸魚川 - 静岡構造線活断層系の最近の断層活動 - 牛伏寺断層・松本市並柳地区トレンチ発掘調査 -
- 64. 大分層群中の火砕流堆積物について(日本火山学会1986年度秋季大会)
- 64 大分層群中の火砕流堆積物について
- 南関東の地震テクトニクスと国府津・松田断層の活動
- 25年後, 地質学は未来を予測する科学になる
- 1896年陸羽地震の地震断層
- 活断層からみた南部フォッサマグナ地域のネオテクトニクス (南部フォッサマグナ・フィリピン海プレ-ト北縁のネオテクトニクス)
- 立川断層とその第四紀後期の運動
- 106. 福井県三方五湖の表層堆積物の層相と地殻変動との関係
- ボ-リング調査で明らかになった丹那盆地の変形構造
- 62A. 古富士および新富士火山噴出物の微量元素(日本火山学会1989年春季大会)
- 235 富山トラフの第四紀地殻変動 : 「しんかい2000」による潜航調査の成果
- 62A 古富士および新富士火山の噴出物の微量元素
- ボーリング調査で明らかになった丹那盆地の変形構造
- 活断層からみた南部フォッサマグナ地域のネオテクトニクス (南部フォッサマグナ・フィリピン海プレ-ト北縁のネオテクトニクス)
- 立川断層とその第四紀後期の運動
- 鎌倉市長谷小路周辺遺跡の液状化跡
- Trenching Study of Okamura Fault of the Median Tectonic Line Active Fault System at Saijo in August, 1988
- 1990 Trenching Study of the Gofukuji Fault of the Itoigawa-Shizuoka Tectonic Line Active Fault System at Namiyanagi, Matsumoto, Central Japan