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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Science / Faculty of Science >
北海道大学地球物理学研究報告 = Geophysical bulletin of Hokkaido University >
第71号 >
火山岩塊の運動再考 (3) : 放出火山岩塊に対する風の効果と岩塊の初速度についてのモデル計算
| Title: | 火山岩塊の運動再考 (3) : 放出火山岩塊に対する風の効果と岩塊の初速度についてのモデル計算 |
| Other Titles: | Reconsideration of volcanic block kinematics (3) : Model calculations considering the effects of the wind and the initial velocity of volcanic block |
| Authors: | 鈴木, 建夫1 Browse this author | | 新井田, 清信2 Browse this author | | 西田, 泰典3 Browse this author | | 大島, 弘光4 Browse this author | | 室伏, 誠5 Browse this author |
| Authors(alt): | Suzuki, Takeo1 | | Niida, Kiyoaki2 | | Nishida, Yasunori3 | | Oshima, Hiromitsu4 | | Murofushi, Makoto5 |
| Issue Date: | 15-Mar-2008 |
| Publisher: | 北海道大学大学院理学研究院自然史科学部門（地球物理学） |
| Journal Title: | 北海道大学地球物理学研究報告 |
| Journal Title(alt): | Geophysical bulletin of Hokkaido University |
| Volume: | 71 |
| Start Page: | 1 |
| End Page: | 18 |
| Abstract: | From the volcano-energetics point of view, it is very important to evaluate the velocity, direction and distribution of ejected volcanic blocks. However, in most cases, it is hard to measure directly such quantities during the eruption. Therefore, the volcanic blocks landed on and around the crater have been investigated to reproduce dynamic aspects of eruption after the eruption. In the present paper, ballistic curves of the volcanic blocks are numerically analyzed for various combination of parameters, such as direction of the explosion principal axis of ejection, velocity and direction of the wind, air resistance to the block and dependence of direction of the initial velocity of ejection. The calculations are made on the basis of a generalized ballistic equation of ejected blocks, in which the wind velocity and the air resistance to the block are treated as vector quantities. Calculated results lead to the following characteristic conclusions: (1)The winds above 20m/s along the direction of ejection plays the major role in the ballistic curves, while the lower wind velocity is less effective. (2) Spatial distribution of the landed blocks is mainly affected by the direction of the explosion principal axis. The distribution of the volcanic blocks which was spread to the specific direction is described by inclination of the explosion principal axis. (3) The spatial distribution of the small size blocks depends remarkably on the air resistance. |
| Type: | bulletin (article) |
| URI: | http://hdl.handle.net/2115/32756 |
| Appears in Collections: | 北海道大学地球物理学研究報告 = Geophysical bulletin of Hokkaido University > 第71号
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