宁河-昌黎断裂基于浅层地震勘探资料研究

Research on the Ninghe-Changli Fault Based on Data from Shallow Seismic Exploration

摘要:

宁河—昌黎断裂长约170 km，为燕山隆起、山海关隆起与黄骅拗陷的分界断裂，断裂西南起自宁河，向东北经南套南、大夫庄南、杨家坨，过昌黎转向东入海，断裂走向NE50°~70°，倾向SE，为上陡下缓的铲形正断层，该断裂为一条地壳基底深断裂，控制了南侧黄骅坳陷北段中、新生代沉积。河北省工程地震勘察研究院于2007年、2014年先后在昌黎、滦南、唐海、丰南布设了4条浅层地震勘探测线对宁河—昌黎断裂进行了探测，浅层地震勘探应用美国GEOMETRICS公司STRATAVISOR NX96高分辨数字地震勘探系统，采用70 kg冲击震源，单边激发多次覆盖观测系统，覆盖次数12次。应用Vista地震处理软件系统，通过对数据进行真振幅恢复、地表一致性振幅补偿等处理方法，获得高质量的地震勘探时间剖面。为获得断裂活动时代的重要信息，通过浅层地震勘探处理过程中的中间数据获得地震剖面时—深转换速度参数，从而获得地震勘探深度剖面，结合测线附近地层层序资料，与地震勘探深度剖面进行对比分析，从而获得断裂的上断点埋深和最新活动时代认识。浅层地震勘探剖面揭示，宁河—昌黎断裂浅部由一条主断层和一条次级断层组成；断层上断点埋深40~110 m，断裂活动时代具有分段活动特征，断裂北段活动时代为晚更新世早期，南段为晚更新世中期；断裂走向为北东的段落，为正断层，走向为北西的段落，以走滑运动为主。

Abstract:

The Ninghe-Changli fault, with a length of about 170 km, is the demarcation between the Yanshan uplift, the Shanhaiguan uplift, and the Huanghua depression. This paper reprocessed and analyzed the data of four shallow seismic survey lines broken in the past. Shallow tectonic and activity characteristics of the Ninghe-Changli fault were then obtained. To obtain a high-quality seismic exploration time profile, the Vista seismic processing software system was applied, and the true amplitude recovery of the data and surface consistency amplitude compensation method were used. To make clear the activity age of the fault, through the intermediate data during the process, a seismic survey depth profile was obtained. The data of the depth profile were then compared with the stratigraphic sequence data near the survey line to obtain the buried depth of the upper breakpoint and the latest age of fault activity. The shallow seismic exploration profile revealed that the shallow part of the Ninghe-Changli fault consists of a main fault and a secondary fault; the shallow depth of the breakpoint on the Ninghe-Changli fault is 40~100 m. Fault activities showed a segmental character:the activity age of the northern part of the fault is early late Pleistocene, and that of the southern part is middle late Pleistocene. The fracture with the NE-trending is a positive fault, and the fracture with the NW-trending is a strike-slip fault.