活断層地形が不明瞭なせん断帯を例とした力学的影響範囲を把握する手法の検討

The Method of grasping the current mechanically influenced zone in a shear zone with unclear active geomorphology

後藤 翠; 島田 耕史   

Goto, Akira; Shimada, Koji

ひずみ速度が大きく活断層地形が不明瞭なせん断帯の存在が指摘されている南九州地域で、力学的な影響範囲を把握するため地表踏査を行い小断層の応力逆解析を行った。その結果、断層の変位センスがせん断帯を規定している東西の応力場と調和的な範囲を把握できた。これにより、応力逆解析手法を用いてせん断帯における地表の力学的影響範囲を推定できる可能性が得られた。

In the South Kyushu, where the existence of shear zones with high strain rate and unclear active fault topography was pointed out, surface reconnaissance was conducted and the reverse stress analysis of small faults was carried out in order to grasp the dynamic influence range. As a result, the displacement sense of the fault was able to grasp the harmonious range with the east-west stress field defining the shear zone. Therefore, the possibility that the stress reverse analysis can estimate the mechanical influence range of the surface of the shear zone was obtained.