南西諸島周辺海域の地磁気異常と構造論
スポンサーリンク
概要
- 論文の詳細を見る
Geomagnetic total intensity anomaly map at sea around the Nansei Syoto (Ryukyu Islands) and the Senkaku Syoto was compiled on the basis of the seven survey cruises carried out by the Hydro-graphic Department of M.S. A. from 1975 to 1982. Geomagnetic anomalies are divided into six zones in accordance with the geomagnetic features and topographic/geological characteristics of the region concerned. Some of the significant magnetic anomalies are analized by means of three-dimensional stacked prism model for better understanding of their tectonic implications. A complicated anomaly zone exists along the Paleo-Ryukyu volcanic Belt and the Ryukyu volcanic belt (KONISHI, 1965) and a magnetic smooth zone is recognized over the area of the Ryukyu geoanticline and the continental slope located to the east of the volcanic zones. It is usually recognized that lo-Tori Sima is a southern end of the Quaternaty volcanic front of the Ryukyu islands. However, the geomagnetic and topographic/geological features suggest that the volcanic chain should extend as for as the nothern part of south Ryukyu along the West Ryukyu knolls group (KATO et al., 1982). The geomagnetic anomaly pattern along the above volcanic chain shows systematic variation, i.e. short-wavelength and intermediate amplitude in the north area, relatively magnetic smooth zone in the central area, and the conspicuous dipole anomalies in the south area. This feature may reflect the difference of the volcanism along the volcanic front which might have resulted from the different tectonic situation between north Ryukyu and south Ryukyu as noted from recent study on tectonics of the Ryukyu Island Arc (KIZAKI, 1978). In addition to the above aspect, the followings are also concluded in this study. (1) The magnetic structure of Suwanose Sima shows the weakly magnetized part in the basement of the uplift. This kind of structure is seem to be important for understanding of the geology and volcanic history of the island. (2) Some of the uplift in the north Ryukyu volcanic belt, i.e. Daiiti-Amami Tai, Torisima Tai and Takara Tikai show the caldera like structures, although the further study should be made for the verification of caldera origin. (3) Some of the uplift of knolls and banks inside of the Tokara volcanic chain have lineaments in topography and are not accompanied by local magnetic anomalies. These characteristics may reveal that these uplifts are composed of the Pre-Miocene basement complex. (4) The lineated magnetic anomaly of positive sign, running NE to SW, is recognized from thebank named "Igyo Sone" to Kume Sima to the west of Okinawa Sima. This positive anomaly belt is identified as the volcanic region characterized by green tuff volcanism in Miocene Age. (5) The magnetic structure on Smt. 812 (24°37'N, 125°08'E) located in the Okinawa Trough and the uplift in the outer margine of the Tunghai Shelf show low magnetizations, suggesting the felsitic intrusive volcanic activity. These results are consistent with the geological/petrological features of them.
- 特定非営利活動法人日本火山学会の論文
- 1986-10-01
著者
関連論文
- 橘湾の重力・地磁気異常とカルデラ構造
- 諏訪之瀬島の地磁気異常と3次元磁気構造
- 1986 年伊豆大島噴火後の航空磁気測量成果とその地球電磁気学的考察; B 火口付近に推定される熱消磁構造
- 三宅島西方・群発地震発生海域の地殻構造と銭州海嶺北部のテクトニス
- 三宅島2000年噴火に伴う水路部の三宅島西方海底調査成果概要
- 最近の航空磁気測量について
- 西太平洋の地形と磁・重力異常から求めた海洋地殻構造と海山の地球物理パラメーター
- B39 伊豆大島の3次元磁気構造と1986年噴火以降の地磁気変化(火山の物理(2),日本火山学会2006年秋季大会)
- トカラ列島中之島の地磁気異常と3次元磁気構造
- 大東海嶺周辺の海山の磁気異常とテクトニクス
- 三次元地磁気インバージョンの方法
- 42A. 水路部による伊豆諸島の航空磁気測量成果(日本火山学会 1984 年度春季大会講演要旨)
- 地形メッシュ自動分割法による重力地形補正
- 107. 南西諸島周辺海域の地磁気異常と地質構造(日本火山学会 1984 年度春季大会講演要旨)
- 南西諸島周辺海域の地磁気異常
- 相模湾・城ケ島沖定点観測ブイ付近の流況解析
- 海洋における地磁気測量のリモ-トセンシングへの応用 (海を探る) -- (海洋物理部門)
- 日本列島とその周辺海域の航空磁気異常の特徴と地殻の磁気的構造に関する予備的考察
- 東京湾・南関東周辺の重力異常と深部構造
- 南西諸島周辺海域の地磁気異常と構造論
- 13. 火山・海山の非均一帯磁モデルとその火山学的意義(日本火山学会 1984 年度春季大会講演要旨)
- 日本海溝南部銚子沖の三つの海山の磁気異常解析結果 : 日本火山学会1980年度春季大会
- 三宅島の3次元磁気構造と2000年噴火によるその変化
- 5.2 硫黄島周辺の海上重力