海斗深渊区十字放炮与POBS精确位置校正  

Cross-lineairgun shooting and accurate relocation of POBS in the“Hadal Deep”

作　　者：李子正 丘学林[1,2,3,4] 张佳政 张浩宇[1,2,3,4] 陈瀚 LI ZiZheng;QIU XueLin;ZHANG JiaZheng;ZHANG HaoYu;CHEN Han(Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China;Southern Marine Science and Engineering Guangdong Laboratory,Guangzhou 511458,China;Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences,Guangzhou 510301,China;University of Chinese Academy of Sciences,Beijing 100049,China;Department of Earth System Sciences,the Chinese University of Hong Kong,Shatin,Hong Kong 999077,China)

机构地区：[1]中国科学院南海海洋研究所,边缘海与大洋地质重点实验室,广州510301 [2]南方海洋科学与工程广东省实验室,广州511458 [3]中国科学院南海生态环境工程创新研究院,广州510301 [4]中国科学院大学,北京100049 [5]香港中文大学,中国香港999077

出　　处：《地球物理学报》2021年第9期3333-3343,共11页Chinese Journal of Geophysics

基　　金：国家重点研发计划(2018YFC0309800);国家自然科学基金项目(91958212,41730532);广东省海洋实验室重大专项(GML2019ZD0204)联合资助.

摘　　要：TS03航次创新性地投放了6台被动源海底地震仪(POBS)到马里亚纳海沟南部“海斗深渊区”,实施了万米级水深的天然地震观测,通过十字放炮获得POBS的精确坐底位置是后续研究工作中至关重要的一环.本文首先对POBS的SEG-Y数据进行裁截误差修复,然后采用直达水波走时反演的方法得到这6个POBS的精确坐底位置,并进行精度分析.结果显示,POBS下沉过程中偏移方向各不相同,偏移距离190~650 m;SEG-Y数据裁截误差修复使拾取的直达水波到时更精确,位置校正的走时残差RMS值显著降低,结合正常时差校正(NMO)方法验证,位置校正精度可达10 m,且海斗深渊陡峭地形造成的折射震相对位置校正结果影响不大.此项POBS坐底位置校正工作,不仅为后续研究提供了可靠基础和保障;同时进一步证明,十字放炮作业结合海底地震仪进行直达水波走时反演,是获取深水区域仪器精确位置的可靠方式.During cruise TS03,six Passive Ocean Bottom Seismometers(POBS)were deployed in the“Hadal Deep”,South Mariana.This is the first time that seismic observation was carried out at 10000 m water depth.In this innovative effort,the accurate locations of POBS obtained by cross-line shooting are virtually important.After processing the trace cutting error of SEG-Y file,the accurate locations of POBS were obtained by travel time inversion of direct water waves,and their accuracy was evaluated.Results show that the POBS′s drift directions are different and drift distances range from 190 m to 650 m.Fixing cutting error of SEG-Y files permitts to pick the arrival time of air-gun signal more accurately,through which the RMS is reduced effectively.We evaluate the accuracy of the relocation results by the Normal Moveout Corrections(NMO)method,and confirm the relocation error is within 10 m.The effect of refraction phase caused by steep trench relief can be eliminated.The relocation of the POBS lays a solid foundation for the following-study,and the direct water wave inversion combined with cross-line shooting and OBS is a reliable way to get accurate positions of deep-sea instruments.

关 键 词：海斗深渊 被动源海底地震仪(POBS) 十字放炮 位置校正 走时反演 正常时差校正(NMO) 

分 类 号：P631[天文地球—地质矿产勘探] P738[天文地球—地质学]