Abstract: A lot of seismic volcanic rocks and strong earthquake-induced thixotropic deformation structures in soft mud-sandy sediments(seismites)were identified from the Upper Cretaceous Shijiatun Member of the Hongtuya Formation for the first time in Jiaozhou City of the Zhucheng Sag, eastern China. Seismic volcanic rocks are volcanic rocks with co-seismic deformation structures which were produced by major earthquakes destroying volcano ejecta. Seismites are sediment layers with soft-sediment deformation structures formed by strong earthquake triggering saturated or semi-consolidated soft sediments to produce liquefaction, thixotropy, faults, cracks and filling and so forth. The Shijiatun Member of the Hongtuya Formation mainly consists of basaltic volcano rocks interbedded with mud-sandy(muddy sand and sandy mud)deposition layers of the river-lake facies. In the Shijiatun Member, main types of seismic volcanic rocks are shattered basalts with co-seismic fissures and seismic basaltic breccias. The thixotropic deformations of soft mud-sandy sediments mainly include thixotropic mud-sandy veins and thixotropic mud-sandy layers with tortuous boundaries. Under the strong earthquake action, saturated mud-sandy sediments could not be liquefied, instead resulting in thixotropy, i.e. their texture can be damaged and their flow-ability or rheology becomes strong. Because basaltic volcano rocks were damaged(shattered, seismic broken), a major earthquake can lead to thixotropic mud-sandy sediments flowing along seismic fissures in basalts, resulting in the formation of deformation structure of thixotropic veins, and boundaries between volcano rock and mud-sand layer became quite winding. Under the koinonia of gravity and vibration force, seismic breccia blocks sunk into thixotropic mud-sandy layers, resulting in the formation of inclusions of thixotropic mud-sandy sediments. Seismic intensity reflected by these strong earthquake records during the end stage of the Late Cretaceous was about Ⅶ to more than X degrees. The Shijiatun Member is mainly distributed in the south of the Baichihe fault in the northern Zhucheng Sag, and the fault has generated many strong tectonic and earthquake activities at the end of the late Cretaceous, also provided the channel for intrusion and eruption of basaltic magma then. At the end of the late Cretaceous, intermittent intrusion and eruption of basaltic magma took place along the Baichihe fault, meanwhile the volcano earthquakes took place or tectonic earthquakes were generated by the Baichihe fault which caused the deformation of the volcano lava and underlying strata of red saturated muddy-sand, resulting in the formation of various seismo-genesis deformations of volcanic rocks interbedded with mud-sandy sediment layers. Therefore, strong seismic events recorded by them should be responses to strong tectonic taphrogenesis of the Zhucheng Sag and intense activity of the Baichihe fault in the end of Late Cretaceous. In addition, these seismogenic deformation structures of rock-soil layers provide new data for the analysis of the failure effect produced by seismic force in similar rock-soil foundations.

Key words: seismic volcanic rock, soft mud-sandy sediment, thixotropic deformation, seismic event record, Jiaozhou City

摘要： 首次从胶州市上白垩统红土崖组史家屯段中识别出了一些震火山岩和强地震引起的软泥砂质沉积物的触变变形构造（震积岩）。震火山岩是强地震破坏火山喷出物形成的具同震变形构造的火山岩。震积岩是强地震触动饱和-半固结的软沉积物发生液化、触变、断裂、裂开、充填等形成的具软沉积物变形构造的沉积岩层。红土崖组史家屯段主要由玄武质火山岩夹河湖相泥砂质（砂质泥和泥质砂）沉积层组成。史家屯段中，震火山岩的主要类型为具同震裂隙的震裂玄武岩和震碎玄武岩（震碎玄武质角砾岩）等；软泥砂质沉积物的触变变形主要包括触变泥砂质脉和具曲折边界的触变泥砂质层。受强地震作用，饱和泥砂质沉积物不会发生液化，但会发生触变，即其结构会被破坏而具较强的流动性。由于玄武质火山岩层被地震破坏（震裂、震碎），强地震致使触变泥砂质沉积物沿玄武岩中的震裂隙而流动，结果形成了触变脉变形构造，也使火山岩层与泥砂质层的边界变得十分曲折。在重力和震动力的联合作用下，被震碎的玄武质岩块沉入触变泥砂质中，形成了触变泥砂质沉积物的包体。这些晚白垩世末期的强地震事件记录，所反映的地震烈度约Ⅶ至Ⅹ度以上。史家屯段主要分布在诸城凹陷北部的百尺河断裂以南地带，晚白垩世末该断裂发生强构造与地震活动，也为当时的玄武岩浆上侵和喷发提供了通道。晚白垩世末，玄武岩浆多次沿百尺河断裂间歇式地上侵和喷发，同时产生的火山地震或由百尺河断裂的活动产生的构造地震，致使火山熔岩和下伏的红色饱和泥砂层发生了上述变形，结果形成了地震成因的火山岩与泥砂质沉积层的变形构造。因此，它们所记录的地震事件，应是晚白垩世诸城凹陷发生强构造裂陷和百尺河断裂发生激烈断裂活动的响应。文中具地震成因的岩土层变形构造，也为分析类似岩土地基的地震力破坏效应提供了新资料。

关键词: 震火山岩, 软泥砂质沉积物, 触变变形, 地震事件记录, 胶州市