| 南海东部次海盆地震背景噪声分析 |
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| 引用本文： | 刘亚楠,刘保华,刘晨光,华清峰,颜文华.南海东部次海盆地震背景噪声分析[J].海洋地质与第四纪地质,2021(2):109-117. |
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| 作者姓名： | 刘亚楠 刘保华 刘晨光 华清峰 颜文华 |
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| 作者单位： | 中国海洋大学海洋地球科学学院;自然资源部第一海洋研究所海洋地质与成矿作用重点实验室;青岛海洋科学与技术试点国家实验室海洋地质过程与环境功能实验室;国家深海基地管理中心;陕西省地震局 |
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| 基金项目： | 国家自然科学基金委员会-山东省人民政府海洋科学研究中心联合资助项目“海洋地质过程与环境”(U1606401);全球变化与海气相互作用专项“西太平洋俯冲带及弧后盆地体系”(GASI-GEOGE-02);“OBS海洋环境噪声数据整编”(GASI-01-01-01-24-OBS);中国大洋矿产资源研究开发协会项目“大西洋靶区多金属硫化物调查区综合地球物理异常与找矿应用”(DY135-S2-2-04);泰山学者工程专项经费(tspd20161007)。 |
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| 摘 要： | 背景噪声的强弱是影响地震台站观测的一个重要因素。获取背景噪声的分布特征对评估海底地震仪记录数据质量及对数据的降噪处理均具有重要的指示意义。利用概率密度函数方法获取台站数据的功率谱密度的概率分布特征并与全球背景噪声高值模型和低值模型进行对比是研究台站周围环境背景噪声水平的有利手段。本研究基于南海大规模的被动源海底地震仪台阵长期观测实验的部分数据,利用概率密度函数方法研究了南海的背景噪声。首先,在全频段上对背景噪声进行了分析,并与其他台站做了对比,发现海洋的背景噪声在微震段和低频段大于高值模型且在全频带上远大于陆基台站的背景噪声,这表明海底地震仪数据质量并不高;其次,对观测过程中出现的地震事件以及其他典型信号的概率密度分布进行了归纳总结,发现远震事件、近震事件和数据丢失现象分别具有不同的优势频段和特征,这对后续滤波处理和质量检查具有重要指示意义;最后,研究了背景噪声的时间变化特征,发现台风是导致微震段时间变化的主要原因。
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| 关 键 词： | 海底地震仪 背景噪声 概率密度函数 南海 |
Research on seismic background noise in the Eastern Subbasin of the South China Sea |
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| LIU Yanan,LIU Baohua,LIU Chenguang,HUA Qingfeng,YAN Wenhua.Research on seismic background noise in the Eastern Subbasin of the South China Sea[J].Marine Geology & Quaternary Geology,2021(2):109-117. |
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| Authors: | LIU Yanan LIU Baohua LIU Chenguang HUA Qingfeng YAN Wenhua |
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| Institution: | (College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;Key Laboratory of Marine Geology and Metallogeny,First Institute of Oceanography,MNR,Qingdao 266061,China;Laboratory for Marine Geology,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266061,China;National Deep Sea Center,Ministry of Natural Resources of China,Qingdao 266100,China;Seismological Bureau of Shaanxi Province,Xi'an 710068,China) |
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| Abstract: | The intensity of background noise is an important factor that affects the observation of seismic stations.Acquiring the characteristics of the background noise is of great significance to the evaluation of the quality of the data recorded by the Ocean Bottom Seismometer(OBS)and the noise reduction of the recorded data.Using the Probability Density Function(PDF)method to obtain the probability distribution characteristics of the Power Spectral Density(PSD)of the recorded data and comparing them with the results of new high-noise model(NHNM)and new low-noise model(NLNM)is a favorable method to research the background noise level around the station.Based on the long-term observation data of a large-scale passive source OBS array in the South China Sea(SCS),the background noise in the SCS is studied by using the PDF method.Firstly,the background noise in the whole frequency band is analyzed and compared with that from other stations.It is found that the background noise in the ocean is greater than the NHNM in the microseisms and low frequency band,and far greater than the background noise of the land-based station in the whole frequency band,which indicates that the data quality of the OBS is poor.Secondly,the probability density distribution of the earthquakes and other signals in the observation process is summarized,and it is found that the teleseismic,near earthquake and data dropout signal have different dominant frequency bands respectively,which has important significance for subsequent filtering processing and quality inspection.Finally,the time variation characteristics of background noise are studied,and it is found that typhoon is the main cause of time variation in microseisms period. |
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| Keywords: | ocean bottom seismometer South China Sea background noise probability density function |
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