| 講演要旨(和文) | | マグマ蓄積期にある桜島火山においてマグマ移動システムの研究を目的とする人工地震実験を行った.この人工地震実験では15 点の発破による人工地震を約700 点の臨時観測点で観測した.そのうちの8点の発破と220点の臨時観測点は姶良カルデラ中央部から桜島火山へのマグマ供給システムの探査を目的として,桜島島内に2本の測線として展開された.2本の測線のうち南北方向の測線では深さ8km, 10kmに明瞭な反射イベントを検出し,その深度はこれまでに提唱されたマグマ供給モデルのそれと一致する。 |
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| | 講演要旨(英文) | | A seismic experiment was carried to obtain background information on magma transportation system of Sakurajima Volcano under the magma accumulation stage. The experiment was a part of the seismic experiment, SAKURAJIMA2008, which was carried in order to constrain seismic structures of Sakurajima volcano and Aira caldera. The experiment includes 15 shot points and about 700 temporary stations. A part of them, 8 shot points and 220 stations, were arranged into lines NS and EW across the presented magma pathway to detect them and to obtain reference structure for forthcoming discussion on 4-D seismic monitoring of Sakurajima Volcano. Reflection analysis was made and successful results are obtained. Some prominent reflection events are detected in the line NS at the 8km and 10km below sea level. These reflection events are inferred to be a part of the possible magma pathway. |
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