福建闽江断裂带第四纪活动特征

Characteristics of Quaternary Activities along Minjiang Fault Zone, Fujian Province

本文通过地貌、第四纪地层、钻探、槽探和浅层地震勘探等资料分析,研究了闽江断裂带第四纪活动特征,并探讨了活动断裂与地震的关系。结果表明:(1)闽侯-南屿断裂展布于旗山东侧山前,与五虎山北麓断裂共同组成北西向的闽江断裂带,控制了福州盆地的西侧和南侧边界;(2)闽江断裂带的活动时代从山地向平原方向逐渐变新,山地基岩内的断裂为中更新世断裂,山前断裂多为晚更新世断裂,呈正断性质,上盘沉积速率为0.78mm/a—1.2mm/a;(3)闽江断裂带及其与北东向断裂交汇部位附近小震活动相对密集。

Through comprehensive analysis of Quaternary strata, drilling, trenching and high-resolution seismic reflection, the characteristics of Minjiang fault and its relation to seismic activity are discussed. The major conclusions include： 1） Minhou-Nanyu fault is distributed along the eastern hill-foot of Mt. Qishan, which closely associated with Balsha-Mazhou NW-trending gravity anomaly and aeromagnetic anomaly belts, forming Minjiang NW-striking fault zone together with Wuhushan fault, which controlling the west and south boundaries of Fuzhou basin; 2） the active age of Minjiang fault is varies from middle Pleistocene in mountain area to late Pleistocene in plain area, which are characterized by normal faulting with the deposition rate of 0.78mm/a--1.2mm/a; 3） the intersections of Minjiang faults with some NE-striking faults are just the places where small earthquakes are concentrated in.