| 講演要旨(和文) | | 本研究は，秋田県南部の砥沢地すべり地において屈折法地震探査を行い，表層地震波速度を調べた．本探査はS波探査とP波探査を同一測線で行った．S波解析ではＳ/Ｎ比を改善するために改良型反転重合を使用した．Ｐ波解析では、波線追跡法使用したフォワードモデリングを通じて地震波速度構造モデルを構築した．解析の結果，S波速度の第一層平均速度は113.4(m/s),第二層平均速度は395.5(m/s)であった．P波速度は，第一層平均速度は120~160m/s,第二層速度は690~730m/sであった．速度構造モデルより，すべり面は３層目上部の境界面もしくは３層目下部に存在することが分かった。 |
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| | 講演要旨(英文) | | Seismic velocity structure is investigated in the landslide site, Tozawa area, Yurihonjo city, south Akita Prefecture. The survey area consists colluvial soil landslide that second order and it have moved repeatedly. The survey length was 72m. S- and P- wave survey was made along the same line. An improved reverse stack was applied in S-wave analysis so as to improve S/N ratio. Seismic velocity structure model was constructed through forward modeling of ray tracing. The ray tracing program SEIS88 is used. As the result of S wave result, averages of the S wave velocity were 113.4(m/s) for the first layer, and 395.5(m/s) for the second layer. And P wave result, averages of the P wave velocity were 120~160(m/s) for the first layer, and 690~730(m/s) for the second layer. Landslide plane can be the second boundary or a hidden boundary in the best velocity model. |
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