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Electric potential gradient changes during explosive activity at Sakurajima volcano, Japan

Lane, Stephen and Gilbert, Jennifer (1992) Electric potential gradient changes during explosive activity at Sakurajima volcano, Japan. Bulletin of Volcanology, 54 (7). pp. 590-594. ISSN 1432-0819

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Abstract

We report electric potential gradient measurements carried out at Sakurajima volcano in Japan during: (1) explosions which generated ash plumes, (2) steam explosions which produced plumes of condensing gases, and (3) periods of ashfall and plume-induced acid rainfall. Sequential positive and negative deviations occurred during explosions which generated ash plumes. However, no deflections from background were found during steam explosions. During periods of ashfall negative electric potential gradients were observed, while positive potential gradients occurred during fallout of plume-induced acid rain from the same eruption. These results suggest that a dipole arrangement of charge develops within plumes such that positive charges dominate in the volcanic gas-rich top and negative charges in the following ash-rich part of the plume. The charge polarity may be reversed for other volcanoes (Hatakeyama and Uchikawa 1952). We suggest that charge is generated by fracto-emission (Donaldson et al. 1988) processes probably during magma fragmentation within the vent, rather than by frictional effects within the plume.

Item Type: Article
Journal or Publication Title: Bulletin of Volcanology
Subjects: UNSPECIFIED
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 51718
Deposited By: ep_importer_pure
Deposited On: 01 Dec 2011 16:28
Refereed?: Yes
Published?: Published
Last Modified: 09 Apr 2014 22:54
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/51718

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