| 講演要旨(和文) | | 福岡県西方沖地震の震源域のほぼ南端にあたる海の中道で反射法調査を行った. 測線は志賀島の南西端を起点に,志賀島から海の中道を縦断するおよそ10kmの舗装道路である.発震点間隔は5m,受振点間隔は10mで,震源にはミニバイブT15000を用いた. 初動の見かけ速度は,基盤岩が露出している志賀島部分では4km/sと速く,沖積の砂層に覆われる東に移るにつれて遅くなり,東端付近では1.5km/sとなった.測線の西部分のイメージングは浅部に留まったが,断層に関係すると思われるいくつかの凹構造の反射面が認められた. |
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| | 講演要旨(英文) | | We conducted a reflection survey across the northern part of Kego fault and Ishido-Uminonakamichi fault. Kego fault is located on the southward extension of the main shock and aftershock of the 20 March 2005 West Off Fukuoka Prefecture Earthquake. The length of the survey line is about 10km, starting from the southwest end of Shikano-shima to east through Uminonakamichi. The source spacing is 5m and receiver spacing is 10m. The source is a MiniVib T15000. Because of the strong impedance contrast, only shallower part is imaged now. Some convex features are considered to be related to the faults. |
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