| 講演要旨(和文) | | 新潟市西部,越後平野の沿岸陸域で陸海接合の地震探査の事前調査として反射法地震探査による浅部地下構造調査を行った.断層推定位置よりも西側では,傾斜の異なる複数の東傾斜の反射面が捉えられ探査深度は1km以上であった.これに対して,断層周辺とその東側では,深度200mまでの反射面が東に緩く傾斜する変形はイメージ出来たが,200m以深の反射面は不明瞭である.その原因として,深度約130mのガス層による発震エネルギーの減衰が考えられる. |
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| | 講演要旨(英文) | | A high resolution seismic reflection survey was conducted in the onshore area of the Echigo plain, Niigata Prefecture. The survey line is parallel to the shoreline and crosses the inferred extension of the Kakudayama toen fault. East dipping reflectors are detected between 100m and 1000m in depth with different dips in the western part of the seismic section. They are interpreted as the Nanatani formation, Teradomari formation, Nishiyama formation and so on. On the contrary, reflectors are poor in depth in the central and eastern part of the section. But deformation probably caused by fault movement are perceived on the seismic section shallower than 200m. This is a preparation of the next seismic survey which will connect onshore and offshore area. |
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