主动源海底地震仪记录数据的时间问题及原因分析

Time problems of recorded data in artificial source ocean bottom seismometer exploration and cause analyses

  • 摘要: 简要概括了国产主动源海底地震仪(OBS)数据处理中常见的时间异常现象,以OBS2020-1测线的实际处理为主并结合了OBS处理中对数据异常校正取得的部分进展为实例,通过检查数据记录格式、计算相邻数据文件间的时间差、对比不同处理方法所得剖面、分析初始时间和采样时间是否异常、使用数据重采样等手段,对OBS时间异常问题进行了分类处理和校正。分析显示,国产OBS在数据记录中普遍存在的时间问题大部分均能解决,通过本文提供的方法可以避免处理不当所导致的OBS地震剖面出现同相轴“断阶”、“倾斜”,甚至“缺失”等现象,确保了有效震相的完整性,有效解决了OBS数据时间异常问题,提高了数据的质量和利用率,为后续开展走时层析成像奠定了良好的基础,并为今后主动源OBS数据处理流程和方法提供了借鉴。

     

    Abstract: Artificial source seismic exploration based on ocean bottom seismometer (OBS) is one of the most effective methods to study the structure of crust and mantle, the seismogenic structure and the submarine mineral resources. In modeling velocity structure, the precise time measurements of recorded data by OBS are the key to ensure the reliability of velocity structure. However, in practical work, OBS placed at the seafloor directly, which is unable to acquire accurate time with the satellite navigation system in time, leads to time error of the recorded data, and its oscillation frequency of the quartz is easily affected by temperature, pressure, instrument properties, etc. Therefore, it is necessary to analyze the reasons of clock errors in the process of data processing to obtain the exact time. The common time errors in Chinese artificial source OBSs data processing were briefly summarized in this study, focusing on the processing of profile OBS2020-1 and combining the other previous correction examples. OBS time problems were classified and corrected through checking the data record format, calculating the time error between the adjacent data files, comparing the difference of profiles obtained by different processing methods, analyzing whether the initial time and sampling time are abnormal, using resample and other methods. The analysis shows that most of the time errors commonly existing in the data records of Chinese OBS can be solved, and the method provided in this paper can avoid “stair” , “incline” , even “missing” of the events in OBS seismic profiles caused by improper handling. It ensures the integrity of the effective seismic phase, and effectively solves the problem of time error of OBS data to improve the quality and utilization of data. This study establishes a good foundation for traveltime tomography, and provides a reference for the processing process and methods of artificial source OBS in the future.

     

/

返回文章
返回