济阳坳陷早第三纪地震事件沉积序列

THE EARLY TERTIARY SEDIMENTARY SEQUENCE OF EARTHQUAKE EVENTS IN JIYANG DEPRESSION

济阳坳陷下第三系沙河街组砂四段上部至砂三段地层中发育有以小规模阶梯状正断层为主、阶梯状正断层与振动扭曲变形构造为主和振动液化砂岩脉为主等3种垂向序列的震积岩。它们分别出现在盆地北部陡坡带、洼陷带和中央隆起带。震积岩的发育是控盆边界断裂强烈幕式活动导致的地震作用的直接结果,不同构造单元具有不同的震积序列,反映了随着距震中越来越远地震作用能量逐渐衰减的过程。根据震积岩发育的层位可以研究边界断裂强烈活动的时期,同时,震积岩在地层剖面中的重复出现表明了边界断裂活动具有周期性和幕式特征。

There are three kinds of vertical sequences of seismites in the lower to middle part of Shahejie Formation in early Tertiary in Jiyang depression, such as the ladder-shaped micro-faults dominated sequence, the micro-fault-vibrational liquidation deformation dominated sequece and the vibrational liquidation sandstone dyke doninated sequece. They have been discovered in northern steep zone, hollow zone and uplifted zone in the basin. The development of seismite is the direct result of seismic action caused by intensive movement of boundary fault of the basin. The different seismite sequences in different strcture units reflect seismic energy reduction away from the epicenter. It is possible to study the intensity and phase of boundary faults of the basin according to the horizons of seismites in stratigrahpic profile. At the same time, the repeated emergence of seismites in strata section shows that the movement of boundary faults are of periodicity and episodicity.