著者

中井 順二 駒沢 正夫 大久保 泰邦

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.96, no.4, pp.185-200, 1987-08-25 (Released:2009-11-12)

参考文献数

15

被引用文献数

2 2

---

Bouguer anomaly map of the Kanto district was compiled. On the whole, gravity anomalies are high in Tsukubasan areas, and low in the central parts of the Kanto plain. Negative anomalies in the Boso peninsula and the Tama hills suggest the basement structures of the sedimentary basins. The Kanto mountains district is bounded on the east by steep gradient of gravity anomaly. The above gravity features can be recognized in the map of the upward continuation. The gravity trend along Narashino, Sakura and Omigawa is more clearly indicated in the map of the first derivative, and the tectonic line covered by sediments can be supposed.In the Izu peninsula and the Tanzawa mountains district, gravity anomalies are rather high and low anomaly zone is recognized between these two areas. The northern border part of this zone correspond to Kannawa fault and Kozu-Matuda fault.Aeromagnetic map was compiled with the data obtained by New Energy Development Organization and Geological Survey of Japan.Generally, the Kanto district is surrounded by intense magnetic anomalies with short wavelength which are distributed along Nasu volcanic zone and Fuji volcanic zone.In the central part of the Kanto plain, weak magnetic anomalies are scattered zonally in the E-W direction. According to the geological and well data, this zone seems to be corresponded to Sambagawa metamorphic belt and these anomalies are presumably caused by the basic or ultrabasic rocks.The Hakone mountains district has sharp anomalies with short wavelengths, and the maximum amplitude of the anomalies reachs 900nT. Low anomaly zones are recognized arround this high anomalies. The source of this low anomalies is not clear, but it is of great interest geologically and geophysically.