Bai K L,Fan C Y,Wan K Y,Zhang C L,Xia S H. 2023. Time problems of recorded data in artificial source ocean bottom seismometer exploration and cause analyses. Acta Seismologica Sinica,45(3):550−567. doi: 10.11939/jass.20220206
Citation: Bai K L,Fan C Y,Wan K Y,Zhang C L,Xia S H. 2023. Time problems of recorded data in artificial source ocean bottom seismometer exploration and cause analyses. Acta Seismologica Sinica,45(3):550−567. doi: 10.11939/jass.20220206

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

  • 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.
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