巻号一覧
後続誌
25 巻 (1980)
- 4 号 p. 217-
- 3 号 p. 137-
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25 巻, 3 号
選択された号の論文の6件中1～6を表示しています
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田沢 堅太郎原稿種別: 論説
1980 年 25 巻 3 号 p. 137-170
発行日: 1980/10/01
公開日: 2018/01/15
ジャーナル フリーDetailed stratigraphic study of the various kinds of the volcanic products of Izu-Oshima volcano prior to the summit caldera formation revealed the following: 1. Great eruptions have occurred every 145 years on an average during 10,000 years prior to the caldera formation. 2. The humus layer remains only in the fall deposits which were formed for the last 10,000 years or thereabout. 3. The predominant wind over Izu-Oshima Island has been in the northeast and in the southwest for the last 7,300 years. Before that, it was often in the east. 4. The eruptions which produce smaller amount of ejecta tend to occur more frequently for Izu-Oshima and Hakone volcanoes. Frequency distribution is expressed in an exponential curve. 5. About 7,300 years ago, a strong steam explosion occurred at the summit crater. A few eruptions immediately after that (O41) produced large amounts of tephra but the successive eruptions formed decreasing amounts of it toward the caldera formation. Compared to the above temporal change in the mode of explosive eruptions beginning 7,300 years ago, the volcanic eruptions during the Younger Oshima age appear to correspond to the earlier half .抄録全体を表示PDF形式でダウンロード (4382K) -
巽 好幸, 鳥居 雅之, 石坂 恭一原稿種別: 論説
1980 年 25 巻 3 号 p. 171-179
発行日: 1980/10/01
公開日: 2018/01/15
ジャーナル フリーFour Neogene volcanic rocks in the Kyushu district, which have been estimated to belong the Setouchi volcanie rocks, yielded different K-Ar ages, i.e., 13.2 Ma (southern part of Oita Pref.), 8.3 Ma (Saga Pref.), ＜4.3 Ma (Uku-Jima) and 3.2 Ma (northern part of Oita Pref.). Only a glassy rock from Mt. Daisango-Yama, southern part of Oita Pref. has a K-Ar age (13 .2 Ma) equivalent to those of the Setouchi volcanic rocks in other districts, i.e., 12±1 Ma. On the basis of different K-Ar ages and petrochemical chracteristics from the Setouchi volcanic rocks, the Sanukite-like volcanic rocks in Kyushu, except for that from the southern part of Oita Pref., are not to be classified as the Setouchi volcanic rocks. It is concluded on the basis of the present and previous results that volcanic activity in the Setouchi volcanic zone occurred 12±1 million years ago and extends as long as 1000 km from the eastern part of the Kyushu area (Mt. Daisango-Yama area) to the Choshi area, as a result of the Miocene plate subduction.抄録全体を表示PDF形式でダウンロード (832K) -
鈴木 貞臣, 山下 済, 渡辺 秀文, 岡田 弘, 西田 泰典原稿種別: 論説
1980 年 25 巻 3 号 p. 181-193
発行日: 1980/10/01
公開日: 2018/01/15
ジャーナル フリーThe first outburst of the recent eruption of Usu Volcano took place in the summit crater at 09:12 a. m. (JST) on August 7,1977 after 32 year’s dormancy. This eruption was preceded by a remarkable earthquake swarm which started 32 hours prior to the eruption. By use of seismic data obtained from a routine station and three temporal stations, the hypocenters of the premonitory earthquakes occurring from 11:00 p.m. on August 6 to 5:20 a.m. on August 7 were determined. Focal depths of these earthquakes range from 0 km to 5.5 km below the sea level. The earthquakes shallower than 1 km were located near the newly formed craters. During the period a micro-earthquake swarm occurred simultaneously near Mt.. Showa-Shinzan at shallow depth less than 1 km.抄録全体を表示PDF形式でダウンロード (1029K) -
中村 真人原稿種別: 論説
1980 年 25 巻 3 号 p. 195-205
発行日: 1980/10/01
公開日: 2018/01/15
ジャーナル フリーIbusuki volcanic field, one of the promising geothermal fields in the southern Kyushu consists of Ata caldera, central cones and Kaimon-dake stratovolcano, which erupted one after another from the latest Pleistocene to ca. 1.000 years ago. The comparison of magma composition and rate of thermal energy release about the Kaimon-dake volcano with those of the central cones, indicates a possibility of presence of enough thermal energy in this volcanic field, which might be released by a coming volcanic eruption in the near future.抄録全体を表示PDF形式でダウンロード (879K) -
気象庁原稿種別: 寄書
1980 年 25 巻 3 号 p. 207-209
発行日: 1980/10/01
公開日: 2018/01/15
ジャーナル フリーPDF形式でダウンロード (240K) -
荒牧 重雄, 中村 一明原稿種別: 寄書
1980 年 25 巻 3 号 p. 210-211
発行日: 1980/10/01
公開日: 2018/01/15
ジャーナル フリーPDF形式でダウンロード (210K)
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