小排列高分辨多道地震系统在岱山岛大桥工程中的应用  

Small scale high resolution multichannel seismic system surveys off Daishan Island

作　　者：张勇 田双凤[2] 周建平[2,3] 方斌 

机构地区：[1]浙江省地球物理地球化学勘查院,浙江杭州310005 [2]国家海洋局第二海洋研究所,浙江杭州310012 [3]国家海洋局海底科学重点实验室,浙江杭州310012

出　　处：《海洋学研究》2008年第4期105-110,共6页Journal of Marine Sciences

基　　金：国家海洋局第二海洋研究所基本科研业务费专项资金资助项目(1441-10)

摘　　要：对运用小排列高分辨多道地震系统获取的岱山岛大桥附近海域高精度的地震数据进行了综合分析和处理，查明了调查区域的工程地质条件，并对两个桥址方案进行了地质条件的对比。采用的地震系统参数：拖缆为24道，道间距为2m，偏移距为46m，枪容积为10in^3，频带范围为1～1000Hz。结果表明：（1）采用了统一方法和流程对岱山岛大桥工程中所获得的地震数据进行分析、处理，保证了两种选址方案调查结果的一致性。（2）舟山本岛-岱西桥位（方案Ⅰ）和舟山本岛-双合山桥位（方案Ⅱ）海底地形平缓，不存在海底滑坡体等不良地质现象，调查区域虽分别有6条和5条断裂，但所有断层的上覆第四系均未发生错断，断裂均为非活动性断裂，两个方案桥位线均具有建桥的良好工程地质条件。（3）与单道地震相比，小排列高分辨多道地震系统能得到更为丰富的地层反射地震数据，而该系统比传统的多道反射地震方法具有作业方便、经济的优势，可见，该调查方法适用于近岸区域浅水工程环境的地质调查工作，是一种方便、实用和经济的地质调查手段。The small scale array and high resolution muhichannel seismic survey system, which is a more shorter streamer, shorter group interval, smaller air gun, shorter shot interval and higher frequency than traditional multichannel seismic survey system, has been used for the bridge project at Daishan Island for the selection of the well geology condition of bridge building site. Its group number of streamer is 24 with 2 meters of group interval. The volume of air gun is 10 in3 and shot offset is 46 meters. Frequency band range is from 1 to 1 000 Hz. In Daishan Island bridge project, we acquired high precision seismic data using this method. The follow conlusion can be indicated through this study. Firstly, this system is suitable for the survey of shallow water and coast project. It is more convenient, practical and economic comparing with the traditional multichannel seimie system. Versus the singleseismic system, more detail reflection information of stratum from the seismic data is acquired. It＇s very suitable for the coastal region of the port, the bridge site, and other engineering project investigations. Secondly, in order to improve the resolution of seismic data for the interpretation, it is necessary to remove the coherent and random noise and to suppress the multiple wave and to correct the tidal difference. So these methods are used, which are F-K transformation, bandpass filter, dynamic correction and tidal correction. Finally, to compare with two survey site seismic data, we used an unified method and procedure to process and analyze the seismic data. Engineering geological condition of the two bridge design line has been acquired through the processing and interpretation of seismic data. Then the geological evidence was provided for proposal of bridge site and route. The 6 faults on the bridge design line No. 1 and 5 faults on the No, 2 have been interpreted, but all the faults can not cut cross the Quaternary stratum according to the seismic profile data, which means all faults are not active now. Acco

关 键 词：多道地震 高分辨率 小排列 

分 类 号：P738.4[天文地球—海洋地质] P75[天文地球—海洋科学]