Japan Geoscience Union Meeting 2022

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[J] Oral

S (Solid Earth Sciences ) » S-VC Volcanology

[S-VC31] Active Volcanism

Wed. May 25, 2022 10:45 AM - 12:15 PM International Conference Room (IC) (International Conference Hall, Makuhari Messe)

convener:Yuta Maeda(Nagoya University), convener:Fukashi Maeno(Earthquake Research Institute, University of Tokyo), Takeshi Matsushima(Institute of Seismology and Volcanology, Faculty of Science, Kyushu University), Chairperson:Kohei Hotta(University of Toyama), Takeshi Matsushima(Institute of Seismology and Volcanology, Faculty of Science, Kyushu University)

10:45 AM - 11:00 AM

[SVC31-07] Re-uplift of Jigokudani, Tateyama volcano, revealed from leveling survey —September 2020–September 2021—

*Kohei Hotta1, Hidenori Takahashi1, Yuya Honda1, Takumi Kenmochi1 (1.University of Toyama)

Keywords:Tateyama volcano, Jigokudani valley, leveling survey, deformation source

Leveling surveys were done in Jigokudani valley, Tateyama volcano, since 2015. Bench marks, which were set along the walkway of the valley, showed subsidence up to 5.6 cm during the four-year period from September 2016 to September 2020. Subsidence was started in 2017–2018 when a new crater was formed at southwestern area of Jigokudani. A dislocation source model by Okada (1992) was applied to the subsidence and a closing crack was obtained (Hotta et al., accepted). During the period from September 2020 to September 2021, ground of Jigokudani was revealed to have re-uplifted (Hotta et al., VSJ fall meeting 2021). Since this deformation cannot explain by the crack obtained for the four-year period from September 2016 to September 2020, we applied a Mogi-type spherical source model (Mogi, 1958). An inflation source was located south of the Koya jigoku and the new fumarolic area where violent fumarole activities have been continued. Its depth was 75 m from the surface and volume change was + 2,100 m3. Because of the simplicity of the applied model, we should consider other models in the future study.
This study was supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, under its Earthquake and Volcano Hazards Observation and Research Program.