TY - JOUR
T1 - Magnetotelluric and temperature monitoring after the 2011 sub-Plinian eruptions of Shinmoe-dake volcano
AU - Aizawa, Koki
AU - Koyama, Takao
AU - Uyeshima, Makoto
AU - Hase, Hideaki
AU - Hashimoto, Takeshi
AU - Kanda, Walaru
AU - Yoshimura, Ryokei
AU - Utsugi, Mitsuru
AU - Ogawa, Yasuo
AU - Yamazaki, Ken'ichi
N1 - Funding Information:
Acknowledgments. We thank A. Watanabe and J. Oikawa for maintenance of the MT site. The observations were conducted under the supervision of the Japan Meteorological Agency. We thank landowners and regional forest offices (Kagoshima and Miyazaki prefectures) for permitting the observations. The geomagnetic data used for the remote-reference processing were provided by the Kakioka Geomagnetic Observatory, Japan Meteorological Agency. Comments by M. Unsworth and an anonymous reviewer significantly improved the manuscript. Helpful reviews and constructive editing by C. Newhall, the guest editor of this special volume, are also greatly appreciated. This work was supported by a Grant-in-Aid from MEXT (KAKENHI No. 22900001, and the Multidisciplinary Research Project for High Strain Rate Zones).
PY - 2013
Y1 - 2013
N2 - 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.
AB - 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.
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U2 - 10.5047/eps.2013.05.008
DO - 10.5047/eps.2013.05.008
M3 - Article
AN - SCOPUS:84884383403
SN - 1343-8832
VL - 65
SP - 539
EP - 550
JO - earth, planets and space
JF - earth, planets and space
IS - 6
ER -