利用海底地震仪数据分析台风对海底环境噪音的影响

The impaction of typhoon on seafloor ambient noise by analyzing the OBS recording data

在海底布设的海底地震仪(OBS)能比较清晰地记录到海底的环境噪音,而台风可以直接或间接地产生可以在海底传播的弹性波,从而影响海底的环境噪音,并在较大程度上影响OBS的数据记录。通过分析台风对工作区的整个影响过程中OBS记录数据的振幅变化,再选择合适的滤波方式,首次发现台风产生的风浪及涌浪在短周期海底地震仪的记录数据上有良好的表现特征,指出了台风对海底环境噪音的另一种可能的影响方式,并由此得出:1)台风产生的风浪和涌浪对海底环境噪音的影响模式不同;2)风浪和涌浪所加强的海底环境噪音的范围和程度不同;3)短周期OBS可以比较清晰地记录涌浪信息,其周期主要是6—8s,且能量稳定(简称"8秒现象")。这3点结论为后期的海洋地震研究和海洋学其他研究提供经验与借鉴。

Ocean Bottom Seismometer （OBS） deployed in the seafloor can record information of ocean ambient noise, and typhoon can generate elastic waves propagating through the seafloor directly or indirectly. These factors cause great changes on OBS recording data to some extent. The OBS data during the process of typhoon was ana- lyzed, and the methods of optimum filter were used in order to separate signals. After those work, we found that wind wave and ground swell were well recorded by short-period OBSs for the first time, and a new mode which typhoon affected seafloor ambient noise was put forward. We get three preliminary conclusions from above analysis： 1 ） Wind wave and ground swell caused by typhoon have their own distinctive modes to affect seafloor ambient noise;2） The range and extent of seafloor ambient noise are obviously different which have been strengthened by two above waves;3） Short-period OBSs can clearly record the information of ground swell, whose dominating peri- od is 6--8 seconds and its energy is generally steady （we call it ＂8-second phenomenon＂ ） ; These results will have great significance for the future research on marine seismology and other aspects of oceanography.