【摘要】 在郯庐断裂带的安丘—夏庄箕状盆地的古近纪朱壁店组厚层冲积层中,发育许多震积岩层。它们是由地震液化、地震裂隙充填、振动塌落、地震断裂和地震沉陷作用而形成的震积岩组合。通过野外观测、室内鉴定和比较地震地质学研究,鉴别出了液化砂岩脉、液化砂岩墙、液化砂岩团块、裂隙充填砂砾岩墙、震塌岩、地震成因层内断裂及地震沉陷构造等震积岩构造。根据震积岩构造的特征和有关的研究成果,本文建立了由A、B和C3个震积岩单元组成的震积岩序列。水饱和砂受强烈振动液化作用形成A单元;随后,由砂砾层或砂层的地震裂隙充填和震动塌落而形成B单元;最后,由层内断裂作用及地面沉陷作用生成C单元;该序列的3个单元反映了厚层冲积物的地震作用全过程。更多还原

【Abstract】 Several seismo-depositional layers developed in the thick bedded alluviums of the Paleogene Zhubidian Formation in the Anqiu-Xiazhuang half graben along the Tancheng-Lujiang fault zone. They were a suit of seismites composed of the seismic liquefaction, seismic-fissure filling, vibration falling, seismic fracturing and earthquake settling. Based on the field survey, laboratory examination as well as comparative seismogeologic study, the authors recognized many seismite structures such as liquefied sand vein, liquefied sand dyke, liquefied sand mass, sandy conglomerate dyke by fissure filling, seismic fall-mass, small-scale seismic intra-layer fracture and seismo-settlement structure, etc. According to features of these seismite structures and some relevant research references, a new seismo-depositional succession of alluvial facies sediments, consisting of A, B and C units, was established in the paper. The unit A was formed by strong vibration liquefaction of water-saturation sand at first, then the unit B formed by seismic-fissure filling and vibration falling, and the unit C produced by intra-layer fracturing and ground settling at last, which reflected the whole seismic function of the thick bedded alluviums. To synthesize the analysis of regional geology and research results before, we proposed that the Paleogene seismites in Anqiu area, Shandong, should be a responses to the intense tectonic activity and strong earthquakes of the Tancheng-Lujiang fault zone during Early Cenozoic.更多还原