十勝岳の火口近傍における力学観測 : 序報

青山 裕; Aoyama Hiroshi; 田中 良; Tanaka Ryo; 橋本 武志; Hashimoto Takeshi; 村上 亮; Murakami Makoto; 成田 翔平; Narita Shohei

タイトル	ja 十勝岳の火口近傍における力学観測 : 序報 en Seismic and geodetic monitoring near the active crater at Tokachidake volcano (preliminary report)
作成者	ja 青山, 裕 en Aoyama, Hiroshi NRID 1000030333595 ja 田中, 良 en Tanaka, Ryo NRID 1000000460361 ja 橋本, 武志 en Hashimoto, Takeshi NRID 1000070283588 ja 村上, 亮 en Murakami, Makoto NRID 1000050370804 ja 成田, 翔平 en Narita, Shohei
アクセス権	open access
権利情報	https://creativecommons.org/licenses/by-nc/4.0/ en Creative Commons Attribution-NonCommercial 4.0 International
主題	NDC 450
内容注記	Abstract en Broadband seismometer and tiltmeter newly installed near the crater of Tokachidake volcano made it possible to observe interesting tilt change events that had not been recognized at Tokachidake before. These events are mainly observed at the Maetokachi West station (MTKW) built in October 2016. The tilt events are roughly classified into the following three types: 1. Oscillating micro tilt fluctuation with a period of about several hundred seconds that is remarkable in the horizontal component of the broadband seismometer, 2. Small tilt change that can be recognized as an event by both the broadband seismometer and the tiltmeter, 3. Tilt change that can be remarkably recognized even in the long-term tilt record. Micro tilt fluctuation in type 1 has an amplitude of about several nanoradian at MTKW and it seems that it appears and disappears in response to the atmospheric pressure change. The oscillation direction of the tilt fluctuation at MTKW is between N35°W and N45°W. Small tilt change in type 2 has an amplitude of several tens to several hundreds of nanoradian at MTKW. Many events show step-like subsidence in the crater direction, but some events with slightly large amplitude show complex time functions. Tilt change in type 3 has an amplitude of several microradian at MTKW that can be recognized even in long-term tilt records. Type 3 events were clearly confirmed from November 1 to November 5, 2019 and on January 20, 2020. Tilt changes that seem to be a series of type 3 events were also observed from around November 25, 2019 to December 7, 2019. These phenomena are thought to reflect some pressure fluctuations in the shallow part near the crater. Similar tilt change events have also been reported in Azumayama volcano. These tilt events may be a universal phenomenon in volcanoes with active fumaroles and hydrothermal activities.
出版者	ja 北海道大学大学院理学研究院
日付	Issued2020-03-19
言語	jpn
資源タイプ	departmental bulletin paper
出版タイプ	VoR
資源識別子	DOI https://doi.org/10.14943/gbhu.83.25 , HDL http://hdl.handle.net/2115/77090
ID	JaLC 10.14943/gbhu.83.25
収録誌情報	PISSN 0439-3503 NCID AN0008976X ja 北海道大学地球物理学研究報告 en Geophysical bulletin of Hokkaido University 巻83 開始ページ25 終了ページ48
ファイル	fulltext GBHU_83_p25-48.pdf 9.69 MB (application/pdf) Issued2020-03-19
コンテンツ更新日時	2023-07-26