南海中央次海盆OBS位置校正及三维地震探测新进展  

Correction of OBS Position and Recent Advances of 3DSeismic Exploration in the Central Sub-Basin of South China Sea

作　　者：张莉[1,2] 赵明辉[1] 王建[1,2] 贺恩远[1,2] 敖威 丘学林[1] 徐辉龙[1] 卫小冬[1,2] 张佳政[1,2] 

机构地区：[1]中国科学院边缘海地质重点实验室,中国科学院南海海洋研究所,广东广州510301 [2]中国科学院大学,北京100049 [3]中国海洋石油深圳分公司技术部,广东广州510240

出　　处：《地球科学（中国地质大学学报）》2013年第1期33-42,共10页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金重大研究计划(No.91028002);国家自然科学基金项目(Nos.41076029;41176053)

摘　　要：南海中央次海盆首次开展的三维海底地震仪(ocean bottom seismometer,OBS)探测试验,对于全面认识南海扩张脊处速度展布特征及海底扩张历史有着重要意义.海底地震仪的位置是研究三维地震结构的关键参数之一,高精度的三维OBS数据处理,决定着后期地震结构反演模型的分辨率与准确性.利用直达水波走时信息,综合最小二乘法反演原理,并采用蒙特卡罗法模拟OBS降落海底的过程,完成了南海中央次海盆试验区39台OBS数据格式转换与位置校正工作;同时探讨了蒙特卡罗法应用于位置校正的精度问题.处理后OBS综合记录剖面中展示了多组清晰可靠、来自珍贝-黄岩火山链下深部结构中的波震相,如、和震相。A three-dimensional （3D） Ocean Bottom Seismometer （OBS） seismic exploration is implemented for the first time in the central sub-basin of South China Sea （SCS）. The velocity distribution in 3D high spatial variability is significant to under- stand the history of expansion and evolution of SCS. However, high-precision 3D data processing determines the resolution and accuracy for the further seismic structure, where OBS position is one of the key parameters in seismic structural study. We use the travel time data of direct water waves to simulate the process of OBS landing on seafloor employing the least squares method and Monte Carlo method. Finally the corrections of OBS positions have been achieved for a total of 39 OBSs in the central subbasin of SCS experiment. Meanwhile the accuracy of Monte Carlo method for relocation has been discussed. A few clear and reliable P-wave seismic phases, such as Pg, ProP and Pn, were discovered in the OBS seismic record sections, which come from deep crust or upper mantle beneath the Zhenbei-Huangyan volcanic chains. These abundant seismic phases provide a strong data foundation to the further modeling of 3D tomography for the central sub-basin of SCS.

关 键 词：海底地震仪 位置校正 蒙特卡罗法 震相 南海中央次海盆 海洋学 

分 类 号：P714[天文地球—海洋科学] P716