JpGU-AGU Joint Meeting 2017

Presentation information

[JJ] Oral

S (Solid Earth Sciences) » S-VC Volcanology

[S-VC49] [JJ] Mitigation of Volcanic disaster - Basic and applied research

Sun. May 21, 2017 10:45 AM - 12:15 PM A08 (Tokyo Bay Makuhari Hall)

convener:Mitsuhiro Yoshimoto(Mount Fuji Research Institute, Yamanashi Prefectural Government), Kazutaka Mannen(Hot Springs Research Institute of Kanagawa Prefecture), Shinji Takarada(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Hisashi Sasaki(Asia Air Survey Co., Ltd.), Chairperson:Yoshikazu Kikawada(Faculty of Science and Technology, Sophia University), Chairperson:Hideyuki Itoh(Faculty of policy studies, Iwate prefectural University)

11:15 AM - 11:30 AM

[SVC49-03] Detecting interior structure in Iwate volcano using muon radiography.

*Hideyuki Itoh1, Hidekazu Kakuno2, Morio Tsuji1, Seima Ichikawa2, Fumihiko Takasaki3, Shinya Narita4 (1.Faculty of policy studies, Iwate prefectural University, 2.Department of Physics, Graduate School of Science and Engineering, Tokyo Metropolitan University, 3.HIGH ENERGY ACCELERATOR RESEARCH ORGANIZATION, 4.Department of Physics, Graduate School of Science and Engineering, Iwate University)

Keywords:muon, spring water, chemical analysis

Recently, radiography for the internal structure of volcanoes using cosmic ray muons has developed and it has produced results in case of Asama volcano and Satsumaioujima (Tanaka et al.2008). We have setup the muon detector in east foot of the Iwate volcano, about 6km from the summit and detected since October 14, 2016. Besides this, our objective is to understand deep underground water flow system on the interior of the volcano, by performing continuous observation of chemical composition of spring water originating from Iwate volcano. And this results of spring water composition compare to the image of the internal structure of Iwate volcano obtained from muography.
The present data taking is stabilized and simple two dimensional image can be obtained.
However, the density length of volcano body obtained from the measurements shows a value considerably different from the actual thickness of the mountain and it is influenced much by the muons coming in from electromagnetic shower or scattering from the surroundings. On the other hand, a comparison of the actually measured density length and distance from the topographic data used a 10m mesh DEM of volcano altitude and from the density distribution, difference of density distribution appeared from the younger volcano body between the elder.
From the chemical composition of the spring water can be divided to two groups as Ca(HCO3)2 type and the SO42- in addition to Ca(HCO3)2. When tritium dating shows values of 13.9-23.5 years were obtained. Particularly for the Oide and Kanazawa springs, the values were respectively 19.4 years and 23.5 years and this indicates the possibility of the groundwater recharged during 1998-2003 eruption crisis to gush out now onwards.