安丘—莒县断裂莒县盆地段晚第四纪以来的活动特征

Active Features of Anqiu to Juxian Fault in the Juxian Basin in Late Quaternary

野外调查研究结果表明,安丘—莒县断裂莒县盆地段是一条晚第四纪以来强烈活动的断层。根据断层走向、活动时代及活动性质的变化,可分为两段。董家坡—武家曲坊段和武家曲坊—太湖段,总长度约30km。从滑动速率的分布来看,董家坡—武家曲坊段全新世早期右旋水平滑动速率为1.83mm/a,垂直滑动速率大约为0.37mm/a;全新世晚期右旋水平滑动速率为0.86mm/a,垂直滑动速率大约为0.17mm/a。武家曲坊—太湖段晚更新世早期断裂右旋水平滑动速率为2.78mm/a,垂直滑动速率为0.65mm/a。全新世晚期右旋水平滑动速率为1.37mm/a。垂直滑动速率为0.18mm/a。上述资料表明,安丘～莒县断裂带盆地段的断裂活动无论是时间上还是空间上都有差异,晚更新世以来断裂的活动性有减弱的趋势,全新世时期断裂的活动北段比南段强。

New results of field investigations show that the Anqiu to Juxian fault in the Juxian basin is an active reverse strike-slip fault in late Quaternary. This fault can be divided into two segments in the light of its strikes, active ages and natures, The Dongjiapo to Wujiaqufang segment in the northeast and Wujiaqufang to Taihu segment in the southwest are dominated by dextral reverse strike-slip displacement since late Pleistocene. The average level slip rate of the Anqiu to Juxian fault in the Dongjiapo to Wujiaqufang segment in the northeast is 0.86 tol.83 mm/a in Holocene, and the average vertical slip rate is 0.17～0.34 mm/a in Holocene. The average level slip rate in the Wujiaqufang to Taihu segment in the southwest is 2.78 mm/a in late Pleistocene, 1.37 mm/a in late Holocene and the vertical slip rate on the fault is 0.18 mm/a in late Holocene.