关键词: 隐伏断裂, 海相层, 地层对比, 上断点, 运动速率, 活动特征

Abstract: On the basis of precise locating of the Haihe buried fault, the characteristics of late Quaternary activity of the fault was identified through drilling, identification of microfossils, stratigraphic correlation and chronological dating, by taking 4 marine strata of late Quaternary ages in Tianjin area as key horizon. The result indicates that the upper breaking point of the Haihe Fault in Tianjin downtown area is buried 21m below ground surface, and the corresponding latest movement of the fault had continued through the late stage of late Pleistocene to the early stage of Holocene. On the Tanggu segment of the fault, however, the upper breaking point is buried 16.4m deep, and its latest active period was in the early and middle stage of Holocene. Therefore, the average vertical movement rate on Tianjin downtown segment since the late stage of late Pleistocene (36,290a BP) can be estimated as 0.248mm/yr, and that on the Tanggu segment since the middle stage of Holocene (7200a BP) may reach 0.333mm/yr. This may indicate that the activity of the Haihe Fault on Tanggu segment (eastern segment) is obviously stronger than that on the Tianjin downtown segment (western segment).

Key words: buried fault, marine strata, stratigraphic correlation, upper breaking point, movement rate, characteristics of fault activity