Seimic risk assesment of active reverse faults based on morphological analysis of Holocene surface faulting

基于全新世地表断层形态分析的活动逆断层地震风险评估

• 批准号: 08680191
• 负责人: SAWA Hiroshi
• 金额: $ 1.6万
• 依托单位: TSURUOKA NATIONAL COLLEGE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08680191/
• 关键词: active fault; seimic risk assesment; Holocene surface faulting; flexural scarp; reverse fault; interpretation of large-scale air photographs; morphological analysis; 断層変位地形

Holocene surface faultings are newly recognized in the eastern boundary faults of the Shonai Plain, the western boundary faults of the Yamagata Basin and the eastern boundary faults of the Kamishiro Basin along the Northem part of Itoigawa-Shizuoka Tectonic Line, based on the interpretation of large-scale air photographs and the field survey. Holocene and late Pleistocene deformation is demonstrated along theses faults, and the degree of faults activity, based on vertical displacement, is class A to B (slip rate ; 0.1-1.5m/ka).Holocen flexural scarps of one to two meters or less in relative height is characteristic deformed feature along these faults, implying that this is resulted from low angle reverse faulting.Holocene flexural scarps are situated one hundred meters to one kilometer off from the piedmont line, which indicates that Holocene reverse faulting migrates to the basin. The fold systems well develop in the study areas, which shows that the folding is related to the late Quaternary faulting in the unconsolidated basin deposits.In conclusion, (1) active reverse faults are associated with Holocene flexural scaps which have very gentle slope, (2) the interpretation of large-scale air photographs is helpful to the recognition of active reverse faults which have high seismic risk.

根据大比例尺航片解释和野外调查，在顺奈平原的东部边界断裂、山形盆地的西部边界断裂和龟城朗盆地沿伊藤川-静冈构造线北段的东部边界断裂中，新发现了全新世地表断裂。这些断裂表现出全新世至晚更新世的变形，根据垂直位移计算，断裂的活动程度为A-B级(滑动速率为0.1-1.5m/ka)，相对高度为1~2米或更小的全新世弯曲陡坎是这些断裂的特征，表明这是低角度逆断裂作用的结果。全新世弯曲陡坎位于距山前100米~1公里处，表明全新世反向断裂向盆地迁移。研究区内褶皱系统发育，表明褶皱与松散盆地沉积中的晚第四纪断裂活动有关。综上所述，(1)活动逆断裂与坡度非常平缓的全新世挠曲景观有关；(2)大比例尺航片的解译有助于识别具有高地震危险性的活动逆断裂。

项目成果

SAWA Hiroshi: "Late Quatermary vertical movement along Kan-nonji faults (eastern boundary fault of the Shonai Plain), Northem Japan, based on drilling" Programs and abstracts for annual meeting of Japan Association of Quatemary Research. 26. 104-105 (1996

SAWA Hiroshi：“基于钻探的日本北部沿 Kannonji 断层（庄内平原东部边界断层）的晚第四纪垂直运动”日本第四纪研究协会年会的计划和摘要。

SAWA Hiroshi: "Holocene surface faulting in the Matsuyama fault (eastem boundary faults of the Shonai Plain), based on the interpretation of large-scale map" Proceeding of the General Meeting of the Association of Japanese Geographers. 50. 236-237 (1996)

SAWA Hiroshi：“基于大比例尺地图解释的松山断层（庄内平原东部边界断层）的全新世地表断层”，日本地理学家协会全体会议论文集。

澤 祥: "庄内平野東縁部の活断層詳細図と断層活動" 地球惑星科学関連学会1998年合同大会予稿集. Sf 02252253s 6 (1998)

Sho Sawa：“庄内平原东缘活动断层和断层活动的详细地图”1998 年地球与行星科学协会联合会议记录 Sf 02252253s 6 (1998)。

澤 祥: "庄内平野東縁の活断層トレンチ調査とその意義-松山断層と観音寺断層" 日本地震学会講演予稿集1997年度秋季大会. A33 (1997)

Sho Sawa：“庄内平原东缘活动断层沟的调查及其意义——松山断层和观音寺断层”日本地震学会1997年秋季会议论文集A33（1997）。

SAWA Hiroshi: "Trenching survey on eastern boundary fault of the Shonal Plain, Northern Japan, and its paleoseismological significance" Abstracts of 1997 Japan Earth and Planetary Science Joint Meeting. A33. (1997)

SAWA Hiroshi：“日本北部浅滩平原东部边界断层的挖沟调查及其古地震学意义”，1997年日本地球与行星科学联席会议摘要。