【摘要】 利用浅层地震勘探资料和钻探资料,揭示出宁波育王山山前隐伏断层的存在.8条浅层地震勘探剖面资料显示,育王山山前隐伏断层距山前600～1 200m,断错盆地基底面,可能向上延伸到盆地底部的第四纪地层中.用光释光测年和孢粉分析方法,对钱家钻孔中的第四纪地层进行了年代确定,认为大楔盆地西缘盆地内的第四纪地层为晚更新世以来的堆积.钻探资料显示,钱家和岭南钻孔组中均揭露出侏罗纪凝灰岩中的断层破碎带和断层面.其中,钱家钻孔联合剖面中断层破碎带宽8.5m,岭南钻孔联合地质剖面中发现2条断层,其中一条断层的破碎带宽5m.岭南DQZK6孔埋深35m的上更新统下段黏土中断层面倾角70°,擦痕近垂直;钱家QJZK8孔中,埋深约35m的黏土层中断层面倾角也为70°.断层晚更新世早期的垂直活动速率为0.034～0.046mm/a,属于晚更新世早期弱活动断层.上断点埋深约35m,断层的错动不会对地面建筑物形成直接破坏.更多还原

【Abstract】 Based on the data of shallow seismic survey and drilling geological profiles,a buried fault has been found.With eight shallow seismic profiles,it is found that the buried fault is 600m to 1200m apart from the front of Yuwangshan in front of Yuwangshan Mountain,cutting the floor of Daxie basin,likely extending into Quaternary strata at the basin bottom.Using OSL dating and sporo-pollen analysis,we study the Quaternary sediment in the bore holes of Qianjia village,and suggest that the Quaternary sediment is late Pleistocene stratum at western margin in Daxie basin.On the composite drilling geological section in Qianjia village,fault fracture zone is 8.5m in width in Jurassic tuff.On the drilling geological section of Liangnan village,we find two faults in Jurassic tuff,one of which is 5m in width.At the depth of 35m in Liangnan DQZK6 drilling hole,fault plane obliquity is 70° in clay,with its slickenside approximately upright.In Qianjia QJZK8 bore hole,fault plane obliquity is also 70° at depth of 35m in clay.Active rate of the fault is 0.034-0.046mm/a in vertical direction,and it is a weak active fault in early period of late Pleistocene.From the exploration result,we obtain the depth of the upper break point of the buried fault as 35m in the front of Yuwang Mountain.The active fault will not directly destroy buildings on ground surface along the fault zone.更多还原