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

基本信息

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

项目摘要

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.

糸鱼川-静冈构造线北部的庄内平原东部边界断层、山形盆地西部边界断层和神代盆地东部边界断层等全新世地表断层，是根据大地震的解释而得到新认识的。比例尺航空照片和实地调查。这些断层沿线展示了全新世和晚更新世变形，根据垂直位移，断层活动程度为A至B级（滑移率；0.1-1.5m/ka）。全新世弯曲陡坎为1至2米或更小相对高度的变化是沿着这些断层的典型变形特征，这意味着这是由低角度反向断层作用造成的。全新世弯曲陡坎位于距断层一百米到一公里的地方。山前线，表明全新世逆断层向盆地迁移。研究区褶皱系统发育良好，表明褶皱与松散盆地沉积物中的晚第四纪断层活动有关。综上所述，（1）活动逆断层与全新世弯折岩相关，坡度非常平缓，（ 2）大比例尺航空照片解译有助于识别地震危险性较高的活动逆断层。