Picture of hydrothermal circulation, magma supply system of Kusatsu Shirane volcano

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K01247
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Natural disaster / Disaster prevention science
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: TERADA AKIHIKO 東京工業大学, 理学院, 講師 (00374215)
• Co-Investigator(Kenkyū-buntansha): 石崎 泰男 富山大学, 大学院理工学研究部(理学), 准教授 (20272891) ; 吉本 充宏 山梨県富士山科学研究所, その他部局等, 研究員 (20334287)
• Co-Investigator(Renkei-kenkyūsha): UEKI Kenta 東京大学, 地震研究所, 研究員 (40646353)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 草津白根火山 / 水蒸気噴火 / 熱水系 / 土壌気体水銀放出

Outline of Final Research Achievements

We have developed a simple method to quantify gaseous elemental mercury (GEM) discharge rates from grounds at volcanic fields. Applying the procedure, we have measured GEM flux distribution around the Shirane pyroclastic cones at Kusatsu-Shirane volcano. As a result, we have found two zones emitting relatively high flux of GEM at south and south-east flanks of the Shirane pyroclastic cones. We consider that the areas are fracture zones connecting between shallow hydrothermal reservoirs and ground surface that can form volcanic craters during future eruptions. In addition, our geologic surveys have revealed that explosive eruptions including phreatic and phreatomagmatic explosions have repeatedly occurred at southern part of the Shirane pyroclastic cones. To detect changes in volcanic activities, observation system such as seismometers should be installed at the southern part of Shirane pyroclastic cones, in addition to the area near Yugama crater lake.

Free Research Field

火山物理学