Magnetotelluric and temperature monitoring after the 2011 sub-Plinian eruptions of Shinmoe-dake volcano
Magnetotelluric and temperature monitoring after the 2011 sub-Plinian eruptions of Shinmoe-dake volcano
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DOI：
10.5047/eps.2013.05.008
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发表时间：
2013-01-01
影响因子：
3
通讯作者：
Yamazaki, Ken'ichi
中科院分区：
文献类型：
--
作者：
Aizawa, Koki;Koyama, Takao;Yamazaki, Ken'ichi
2011年1月26日至27日，日本雾岛火山群的新萌岳火山发生了三次普林尼亚喷发。在这一事件中，GPS和倾斜仪检测到火山西北约7公里处的同步喷发地面沉降。从2011年3月开始，我们进行了宽带大地电磁（MT）测量位于5公里的火山，在其下的Shinmoe-dake岩浆管道系统可能存在的NNW的网站。此外，2011年7月开始对MT场址附近的温泉和温泉进行温度监测。我们的MT数据记录了约+/-5%的视电阻率变化，沿着变化+/- 1度。阻抗张量的非对角分量（Z（xy）和Z（yx））中的相位变化。使用1-D反演，我们推断，这些轻微的电阻率变化发生在相对较浅的深度只有几百米，在近地表电阻层和下面的导电层之间的过渡。自2012年3月以来观测到的电阻率变化与MT监测点周围观测到的温度升高相关。这些观察结果表明，存在的MT网站下的途径，使挥发性逃逸。
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 degrees. phase change in the off-diagonal component of the impedance tensor (Z(xy) 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.