营口潍坊断裂带新生代活动的特征

ACTIVE CHARACTERS OF THE YINGKOU WEIFANG FAULT ZONE IN THE CENOZOIC ERA

营潍断裂带以北西向北京 蓬莱断裂带与之交汇的部位为界分南北两段,北段由辫状交织的两条断裂组成;南段为并列的东西两支断裂,但被黄北、莱北和潍北等北东东向断裂横切成4节。断裂带北段早第三纪水平拉张和垂直差异活动强烈,控制了断陷盆地的发育,晚第三纪—第四纪右旋走滑活动显著。南段本身活动甚弱,但黄北等横向断裂早第三纪水平拉张和垂直差异活动强烈,相应形成了黄北等几个断陷盆地;晚第三纪—第四纪横向断裂仍有活动。断裂带活动具明显的分段性,南段是受横向断裂强烈分割、改造而被“废弃”的一段。断裂带新生代活动具由南部和北部统一向中部迁移的特点,北段还有向东侧迁移的趋势。断裂带地震活动微弱,渤海中部斜穿断裂带分布的北东向地震带,可能是黄河口聊城新生地震构造带向海区延伸的部分。

The Yingkou—Weifang fault zone, which is practically one part of Tanlu fault zone in Liaohe—Bohai, lies in the east edge of Bohai Gulf Cenozoic rift basin. It can be divided into two parts, the northern and southern part, by the Beijing-Penglai fault zone. The northern part consists of two faults which interweave like a braid each other. The southern part consists of two parallel faults, and is cut into four parts by Huangbei, Laibei, and Weibei NEE trending fault. The horizontal stretch and vertical movement of the northern part of the fault zone are strong in the Paleogene period, controlls the rifting basin development; nevertheless the right-lateral slip has been prominent since the late Oligocene. The activity of the southern part is weak in the Cenozoic Era, but the cross faults have evident horizontal stretch and vertical action. In the Cenozoic Era, the activity of the fault zone migrated to the middle part from the northern and southern part, and the activity of northern part probably also had the trend from west to east. A NE trending seismic zone, which obliquely cross the Yingkou-Weifang fault zone in the middle of Bohai, is probably the extending part of the Huangheko Liaocheng newly generated seismotectonic zone towards the sea.