海底地震仪的优化设计
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摘要
海底地震仪可用于探测航行舰船地震波信号。然而,由于信噪比较低,容易造成试验数据的失真。主要原因是海底地震仪(OBS)与海底表面的耦合较差。本文根据现有的OBS与沉积物耦合理论,总结了OBS的设计方法:①最小化质量;②合理的与沉积物接触部分的半径;③OBS接近于周围介质的密度;④最小化水中OBS的剖面以及横切面;⑤低密度梯度及关于垂直轴的最大对称性。结合理论,对现役的海底地震仪进行了结构分析。
Ocean bottom seismometer(OBS)can be used to detect seismic wave for the moving ship.But data quality from experiments has often been disappointing because of low signal-to-noise ratio(SNR).Many of these problems result from motion of the OBS package that is decoupled from motion of the ocean floor.In this paper the theory of coupling of OBSs to soft sediments has been summarized.And arrive at results suggesting that OBS packages should be designed with:① the minimum mass,② the rational radiu of area in contact with the sediment,③ density of the OBS approximately ambient medium,④ a low profile and a small vertical cross section with water,and ⑤ low density gradients,and maximum symmetry about the vertical axis.Besides structural analysis has been done for the commissioned OBS based on the theory.
Ocean bottom seismometer(OBS)can be used to detect seismic wave for the moving ship.But data quality from experiments has often been disappointing because of low signal-to-noise ratio(SNR).Many of these problems result from motion of the OBS package that is decoupled from motion of the ocean floor.In this paper the theory of coupling of OBSs to soft sediments has been summarized.And arrive at results suggesting that OBS packages should be designed with:① the minimum mass,② the rational radiu of area in contact with the sediment,③ density of the OBS approximately ambient medium,④ a low profile and a small vertical cross section with water,and ⑤ low density gradients,and maximum symmetry about the vertical axis.Besides structural analysis has been done for the commissioned OBS based on the theory.
引文
[1]卢再华,张志宏,顾建农.舰船海底地震波形成机理的理论分析[J].应用力学学报,2007,(3):54-57.
[2]Sutton G H,Duennebier F K.Optimum design of oceanbottom seismometers[J].Marine Geophysical Researches,1987,(9):47-65.
[3]Sutton G H,Duennebier E K,Iwatake B.Coupling of oceanbottom seismometers to soft bottoms[J].MarineGeophysical Researches,1981,(5):35-51.
[4]Lewis B TR,Tuthill J D.Instrumental waveform distortionon ocean bottom seismometers[J].Marine GeophysicalResearches,1981,(5):79-85.
[5]Duschenes J D,Barash T W,Mattaboni P J,et al.On theuse of an externally deployed geophone package on anocean bottom seismometer[J].Marine GeophysicalResearches,1981,(4):437-450.
[6]Trehu A M,Solomon S C.The coupling parameters of theMIT OBS at two nearshore sites[J].Marine GeophysicalResearches,1981,(5):69-78.
[2]Sutton G H,Duennebier F K.Optimum design of oceanbottom seismometers[J].Marine Geophysical Researches,1987,(9):47-65.
[3]Sutton G H,Duennebier E K,Iwatake B.Coupling of oceanbottom seismometers to soft bottoms[J].MarineGeophysical Researches,1981,(5):35-51.
[4]Lewis B TR,Tuthill J D.Instrumental waveform distortionon ocean bottom seismometers[J].Marine GeophysicalResearches,1981,(5):79-85.
[5]Duschenes J D,Barash T W,Mattaboni P J,et al.On theuse of an externally deployed geophone package on anocean bottom seismometer[J].Marine GeophysicalResearches,1981,(4):437-450.
[6]Trehu A M,Solomon S C.The coupling parameters of theMIT OBS at two nearshore sites[J].Marine GeophysicalResearches,1981,(5):69-78.
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