| 青藏高原东北缘祁连山地区地震台阵背景地噪声特征 |
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| 引用本文： | 郭瑛霞,张元生,董传雷,彭澎,张荣杉.青藏高原东北缘祁连山地区地震台阵背景地噪声特征[J].地震地磁观测与研究,2020,41(5):56-62. |
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| 作者姓名： | 郭瑛霞 张元生 董传雷 彭澎 张荣杉 |
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| 作者单位： | 1.中国江苏 223800 江苏省地震局宿迁地震台;2.中国甘肃 730000 中国地震局兰州地震研究所 |
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| 基金项目： | 中国地震局地震预测研究所基本科研业务费专项（项目编号：2017IESLZ08）和中国地震局地震科技星火计划（项目编号：XH20060）；宿迁市防震减灾“十三五”发展规划重大课题研究（项目编号：S201509） |
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| 摘 要： | 基于祁连山地区78个地震台站的垂直分量连续波形记录，计算台站对之间背景噪声的互相关函数，并叠加得到5-10 s和10-20 s两个周期的瑞利面波信号。利用归一化振幅方法，分析不同周期范围的噪声源能量在不同方位随季节变化的规律。研究结果显示：祁连山地区5-10 s周期背景噪声的能量优势来源，夏季集中在110°-170°方位，冬季集中在300°-350°方位，但在110°-150°方位也有相对微弱的能量分布，表明第二微震带的噪声能量来源在夏季主要来源于太平洋的海洋活动，冬季主要来源于大西洋的海洋活动；10-20 s周期背景噪声的能量优势来源在夏季集中在70°-150°和170°-230°方位，在冬季则集中在290°-350°和70°-130°方位，表明第一微震带的噪声能量在夏季主要来源于印度洋的海洋区域，冬季主要来源于北大西洋和太平洋。由于2个周期的背景噪声源在祁连山地区存在明显的季节差异，因此在利用背景噪声方法研究该地区介质速度结构时，需充分考虑噪声源非均匀性产生的影响。
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| 关 键 词： | 祁连山 互相关函数 背景噪声源 信噪比 归一化振幅方法 |
Analysis of background noise characteristics of the seismic array in Qilian Mountains region,the northeast edge of Qinghai-Tibet Plateau |
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| GUO Yingxia,ZHANG Yuansheng,DONG Chuanlei,PENG Peng,ZHANG Rongshan.Analysis of background noise characteristics of the seismic array in Qilian Mountains region,the northeast edge of Qinghai-Tibet Plateau[J].Seismological and Geomagnetic Observation and Research,2020,41(5):56-62. |
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| Authors: | GUO Yingxia ZHANG Yuansheng DONG Chuanlei PENG Peng ZHANG Rongshan |
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| Institution: | 1.Suqian Seismic Station, Jiangsu Earthquake Agency, Jiangsu Province 223800, China;2.Lanzhou Institute of Seismology, China Earthquake Administration, Gansu Province 730000, China |
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| Abstract: | Based on the continuous wave records of the vertical component of 78 stations of the seismic array in the Qilian Mountains region, the cross-correlation functions of background noise for each station-pair is calculated and the Rayleigh surface wave signals with periods of 5-10 s and 10-20 s are obtained by superposition. The seasonal variation law of noise source energy in different directions for different periods is analyzed and studied by the method of normalized amplitude. The results show that the dominant energy source of 5-10 s period background noise in the Qilian Mountain area is from 110° to 170° in summer, and from 300° to 350° in winter, but there is also a relatively weak energy distribution in 110° to 150° direction, so it indicates that the second microseismic belt mainly comes from the ocean activity in the Pacific Ocean in summer and from the ocean activity in the Atlantic Ocean in winter. The dominant energy sources of 10-20 s periodic background noise are 70° -150° and 170°-230° in summer, and 290°-350° and 70° -130° in winter. The noise energy of the first microseismic belt mainly comes from the sea area of the Indian Ocean in summer and North Atlantic and Pacific in winter. Because the ambient noise source of these two periods has an obvious seasonal variation in the Qilian Mountain area, the influence of inhomogeneity of noise sources should be taken into consideration when the method of ambient noise is used to study the seismic velocity structure in the region. |
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| Keywords: | Qilian Mountains region cross-correlation function ambient noise source signalto-noise ratio normalized amplitude method |
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