The observation of point-discharge current was carried out during the period of from March 25 to April 17. We found three types of anomalous changes, that is, (1) the change, which suddenly commenced and gradually recovered, (2) ones that gradually commenced and suddenly rocovered, and (3) ones that commenced and recovered in a very short time, about in a few minutes. While on the other hand, corresponding .to the above mentioned three anomalous changes we observed the following three conditions respectly : the tranceferance of the belt of volcanic smoke from west to east ; the tranceferance of the belt from east to west ; the falling of ashes notwithstanding that there was no smoke overhead. Moreover, we observed that the eastern edge of the smoke belt was everytime thicker nan the other cdge. This phenomenon will be explained as follows. When the smoke is drifted by the wind southward from the crater, the charged particles shifted from its eourse due to the force caused by the vertical component of the goomagnetic field, resulting that the smoke becomes concentrated in the east edge of the belt. From this assumption mentioned above, the first and the second anomalous changes will be explained obviously. The short period change (the third type of anomaly) will be explained as the anomalous, increasing of the space charge caused by the falling ashes. They were observed while the voloanic smoke belt had come near the zenith. While, the activity of the volcano has the period of few minute, 6 minutes in average. Hence, we believe that the mass of smoke, having electric charge of 0.3 to 0.5 Coulombs, are drifted successively on the wind from the crater. We hope to carry out, in future, the more direct measurement of the preperties of the volcanic smoke.
雑誌名
東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo
巻
24
号
1-4
ページ
221 - 227
発行年
1948-06-30
ISSN
00408972
書誌レコードID
AN00162258
フォーマット
application/pdf
日本十進分類法
453
出版者
東京大学地震研究所
出版者別名
Earthquake Research Institute, University of Tokyo
19. 櫻島火山の噴煙雲による尖端放電電流
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