Japan Geoscience Union Meeting 2022

Presentation information

[J] Poster

M (Multidisciplinary and Interdisciplinary) » M-TT Technology & Techniques

[M-TT45] Brand-new scope of coupling geophysics being established by infrasound and associated waves

Mon. May 30, 2022 11:00 AM - 1:00 PM Online Poster Zoom Room (39) (Ch.39)

convener:Masa-yuki Yamamoto(Department of systems engineering, Kochi University of Technology), convener:Mie Ichihara(Earthquake Research Institute, University of Tokyo), convener:Takayuki Otsu(Japan Weather Association), Chairperson:Masa-yuki Yamamoto(Department of systems engineering, Kochi University of Technology)

11:00 AM - 1:00 PM

[MTT45-P01] Short-term gravity changes observed in and around Kussharo Caldera, Eastern Hokkaido, Japan

★Invited Papers

*Kazunari Nawa1, Yuichi Imanishi2, Hiroshi Ikeda3, Ryo Honda4, Daisuke Oka5, Tatsuo Shirakawa6, Takuma Oi7, Hiroaki Takahashi8, Mako Ohzono8, Hiroshi Aoyama8, Kazumi Okada8, Teruhiro Yamaguchi8 (1.National Institute of Advanced Industrial Science and Technology, 2.ERI, Univ. Tokyo, 3.KEK, 4.MFRI, 5.HRO, 6.Kitami Inst. Tech., 7.Toho Mercantile Co., 8.Hokkaido Univ.)

We aim to detect changes in gravity due to subsurface magmatic activity, fault movement, and related changes in physical properties and crustal deformation around the Kussharo caldera by using an effective combination of a superconducting gravimeter which enables long-term stable observations, an absolute gravimeter which is drift-free, and a spring-type relative gravimeter which is portable and capable of continuous measurements. Continuous observation by iGrav superconducting gravimeter was started at Teshikaga Observatory, Hokkaido University in November 2018. As a result, seasonal changes in gravity were detected, mainly caused by changes in the mass of land water such as soil moisture and snow cover. However, the residual gravity time series after land water corrections indicated short-term changes other than hydrological signals. Possible sources of these short-term gravity changes include the effects of near- and far-field earthquakes, and ground vibrations caused by pressure fluctuations and/or lake water level changes. To investigate the causes of these changes, we have additionally installed field observations, such as a relative gravity meter deployed in the Kussharo caldera area, water pressure (water level) meters installed in Lake Kussharo, a microbarometer and a snow load gauge installed at the Teshikaga Observatory. We will present results of comparison of the data from these new observations with the gravity changes from the superconducting gravimeter.