Magnetotelluric and temperature monitoring after the 2011 sub-Plinian eruptions of Shinmoe-dake volcano

Koki Aizawa, Takao Koyama, Makoto Uyeshima, Hideaki Hase, Takeshi Hashimoto, Walaru Kanda, Ryokei Yoshimura, Mitsuru Utsugi, Yasuo Ogawa, Ken'ichi Yamazaki

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12 Citations (Scopus)

Abstract

Three sub-Plinian eruptions took place on 26-27 January 2011 at Shinmoe-dake volcano in the Kirishima volcanic group, Japan. During this event, GPS and tiltmeters detected syn-eruptive ground subsidence approximately 7 km to the WNW of the volcano. Starting in March 2011, we conducted broad-band magnetotelluric (MT) measurements at a site located 5 km NNW of the volcano, beneath which the Shinmoe-dake magma plumbing system may exist. In addition, temperature monitoring of fumaroles and hot-springs near the MT site was initiated in July 2011. Our MT data record changes in apparent resistivity of approximately ±5%, along with a ±1° phase change in the off-diagonal component of the impedance tensor (Zxy and Z yx). Using 1-D inversion, we infer that these slight changes in resistivity took place at relatively shallow depths of only a few hundred meters, at the transition between a near-surface resistive layer and an underlying conductive layer. Resistivity changes observed since March 2012 are correlated with the observed temperature increases around the MT monitoring site. These observations suggest the existence beneath the MT site of pathways which enable volatile escape.

Original languageEnglish
Pages (from-to)539-550
Number of pages12
Journalearth, planets and space
Volume65
Issue number6
DOIs
Publication statusPublished - 2013

All Science Journal Classification (ASJC) codes

  • Geology
  • Space and Planetary Science

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    Aizawa, K., Koyama, T., Uyeshima, M., Hase, H., Hashimoto, T., Kanda, W., Yoshimura, R., Utsugi, M., Ogawa, Y., & Yamazaki, K. (2013). Magnetotelluric and temperature monitoring after the 2011 sub-Plinian eruptions of Shinmoe-dake volcano. earth, planets and space, 65(6), 539-550. https://doi.org/10.5047/eps.2013.05.008