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Three-dimensional resistivity structure and magma plumbing system of the Kirishima Volcanoes as inferred from broadband magnetotelluric data

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Please use this identifier to cite or link to this item:http://hdl.handle.net/2115/67566

Title: Three-dimensional resistivity structure and magma plumbing system of the Kirishima Volcanoes as inferred from broadband magnetotelluric data
Authors: Aizawa, Koki Browse this author
Koyama, Takao Browse this author
Hase, Hideaki Browse this author
Uyeshima, Makoto Browse this author
Kanda, Wataru Browse this author
Utsugi, Mitsuru Browse this author
Yoshimura, Ryokei Browse this author
Yamaya, Yusuke Browse this author
Hashimoto, Takeshi Browse this author →KAKEN DB
Yamazaki, Ken'ichi Browse this author
Komatsu, Shintaro Browse this author
Watanabe, Atsushi Browse this author
Miyakawa, Koji Browse this author
Ogawa, Yasuo Browse this author
Issue Date: 2014
Journal Title: Journal of Geophysical Research : Solid Earth
Volume: 119
Issue: 1
Start Page: 198
End Page: 215
Publisher DOI: 10.1002/2013JB010682
Abstract: Broadband magnetotelluric (MT) measurements were conducted in 2010 and 2011 in the vicinity of Shinmoe-dake Volcano in the Kirishima volcano group, Japan, where sub-Plinian eruptions took place 3 times during 26–27 January 2011. By combining the new observations with previous MT data, it is found that an anomalous phase in excess of 90° is commonly observed in the northern sector of the Kirishima volcano group. Because the anomalous phase is not explained by 1-D or 2-D structure with isotropic resistivity media, 3-D inversions were performed. By applying small errors to the anomalous phase, we successfully estimated a 3-D resistivity structure that explains not only the normal data but also the anomalous phase data. The final model shows a vertical conductor that is located between a deep-seated conductive body (at a depth greater than 10km) and a shallow conductive layer. By applying the findings of geophysical and petrological studies of the 2011 sub-Plinian eruptions, we infer that the subvertical conductor represents a zone of hydrothermal aqueous fluids at temperatures over 400°C, in which a magma pathway (interconnected melt) is partially and occasionally formed before magmatic eruptions. To the north of the deep conductor, earthquake swarms occurred from 1968 to 1969, suggesting that these earthquakes were caused by volcanic fluids.
Rights: Copyright 2014 American Geophysical Union.
Type: article
URI: http://hdl.handle.net/2115/67566
Appears in Collections:理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 橋本 武志

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