2024-03-29T05:51:50Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/215032022-11-17T02:08:08Zhdl_2115_20574hdl_2115_13714hdl_2115_116阿寒カルデラとその周辺の重力構造Gravity Structure of the Akan Caldera and Its Vicinity, Eastern Hokkaido, Japan長谷川, 健HASEGAWA, Takeshi山本, 明彦YAMAMOTO, Akihiko神山, 裕幸KAMIYAMA, Hiroyuki中川, 光弘NAKAGAWA, Mitsuhiroopen access450.12We performed gravity surveys and compiled pre-existing gravity data to obtain gravity anomalies of the Akan Caldera, eastern Hokkaido, and a new gravity map around the caldera was produced. In particular, we conducted gravity surveys on the frozen lake surface in winter to reveal a fine gravity structure. A new Bouguer anomaly map shows that the Akan Caldera is characterized by three closed mimima and takes its minimum value(~70mgal)in the central area of the caldera. It is consistent with our geologic studies suggesting that the Akan Caldera is multiple caldera. Characteristic low anomalies in the Akan Caldera gradually increase towards topographic rim outside and reach their maximum around the rims. Post-caldera volcanoes are distributed not along topographic caldera rim but along a periphery of the low-anomaly region, which is situated inside the topographic rim.北海道大学大学院理学研究科地球惑星科学専攻(地球物理学)2006-03-15jpndepartmental bulletin paperVoRhttps://doi.org/10.14943/gbhu.69.97http://hdl.handle.net/2115/2150310.14943/gbhu.69.970439-3503AN0008976X北海道大学地球物理学研究報告Geophysical bulletin of Hokkaido University6997112https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/21503/1/08.pdfapplication/pdf39.75 MB2006-03-15