基于概率统计的甚宽频带地震计自噪声水平分析
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摘要
使用连续1000hr的数据计算甚宽频带地震计自噪声,应用概率统计方法对计算结果进行分析,分别以单小时结果众值、单频点概率统计及分频带概率统计等3种表达方式对分析结果进行展示。通过比较分析,发现第1种方式便于异常结果溯源,但无法获取自噪声非均匀分布特征;第2种方式可以获取固定频点上自噪声水平非均匀分布的详细特征,但高概率值呈现条带分布,没有明显量级差异;第3种方式得到了对应于中心频点的且具有量级差异的高概率值,为地震计自噪声的数学数值建模提供了支持。在异常数据数量较少的情况下,异常结果在后2种方式中得不到体现。
we calculated the seismometer's self-noise level with 1000 consecutive hours of data,and proposed using the probability and statistics method to analyze the calculation results. the analysis results are demonstrated by three expressions: multi-hour result overlap,probability statistics on single frequency point and probability statistics in subband. Through the comparison and analysis,we found that it is easy to track anomalies but hard to get the non-uniform distribution characteristic for the first expression. For the second one,it is easy to get the non-uniform distribution characteristic of the self-noise level at the fixed frequency point without obvious difference in orders of magnitude. the third method is to obtain a high probability value corresponding to the center frequency point and having a magnitude difference. In the case of a small amount of abnormal data,the abnormal results are not reflected in the latter two ways.
we calculated the seismometer's self-noise level with 1000 consecutive hours of data,and proposed using the probability and statistics method to analyze the calculation results. the analysis results are demonstrated by three expressions: multi-hour result overlap,probability statistics on single frequency point and probability statistics in subband. Through the comparison and analysis,we found that it is easy to track anomalies but hard to get the non-uniform distribution characteristic for the first expression. For the second one,it is easy to get the non-uniform distribution characteristic of the self-noise level at the fixed frequency point without obvious difference in orders of magnitude. the third method is to obtain a high probability value corresponding to the center frequency point and having a magnitude difference. In the case of a small amount of abnormal data,the abnormal results are not reflected in the latter two ways.
引文
万永革,2012,数字信号处理的MATLAB实现,2版,北京:科学出版社.
廖诗荣、陈绯雯,2008.应用概率密度函数方法自动处理地震台站勘选测试数据,华南地震,28(4),82-92.
Carter G, Knapp C,Nuttall A, 1973, Estimation of the magnitude-squared coherence function via overlapped fast Fourier transform processing,IEEE Trans Audio Electroacoustics,21(4),337-344.
Davis J P,Berger J,2007,Calibration of the global seismographic network using tides,Seismol Res Lett,78(4),454-459.
J R Evans,F Followill,C R Hutt, et al, 2010, Method for calculating self-noise spectra and operating ranges for seismographic inertial sensors and recorders,Seismol Res Lett,81(4),640-646.
Ekstrom G, Dalton C A, Nettles M, 2006, Observations of time-dependent errors in long-period instrument gain at global seismic stations,Seismol Res Lett,77(1),12-22.
Gerner A, Sleeman R, Lenhardt W,et al, 2016, Improving self-noise estimates of broadband seismometers by 3D trace rotation,Seismol Res Lett,88(1),96-103.
Holcomb L G,1989, A direct method for calculating instrument noise levels in side-by-side seismometer evaluations,Albuquerque,New Mexico:U.S. Geological Survey.
Holcomb L G, 1990, A numerical study of some potential sources of error in side-by-side seismometer evaluations, Albuquerque, New Mexico:U.S. Geological Survey.
Hutt C R, Evans J R, Followill F,et al,2010, Guidelines for standardized testing of broadband seismometers and accelerometers,Reston, Virginia:U.S. Geological Survey.
Li X J,Yang D K,Xie J B,et al,2015, Applicability of the Welch method for examining self-noise level parameters for broadband seismometers,Geodesy Geodyn,6(3),233-239.
Oppenheim A V,Schafer R W,Yuen C K,1978,Digital signal processing,IEEE Trans Syst,Man,Cybem,SMC-8(2),146.
Me Namara,D E,2004, Ambient Noise Levels in the Continental United States,Bull Seismol Soc Am,94(4),1517-1527.
Peterson J R, 1993, Observations and modeling of seismic background noise, U.S.Geological Survey Open File Report,94.
Ringler A T,Gee L S,Hutt C R,et al,2010a,Temporal variations in global seismic station ambient noise power levels,Seismol Res Lett,81(4),605-613.
Ringler A T,Hutt C R,2010b,Self-noise models of seismic instruments,Seismol Res Lett,81(6),972-983.
Ringler A T,Hutt C R,Evans J R, et al, 2011, A comparison of seismic instrument noise coherence analysis techniques, Bull Seismol Soc Am, 101(2),558-567.
Ringler A T,Sleeman R, Hutt C R, et al, 2014, Seismometer self-noise and measuring methods, In:Beer M, Kougioumtzoglou I,Patelli E,et al, Encyclopedia of Earthquake Engineering, Berlin, Heidelberg:Springer.
Sleeman R,Melichar P,2012, A PDF representation of the STS-2 self-noise obtained from one year of data recorded in the Conrad observatory,Austria,Bull Seismol Soc Am,102(2),587-597.
Sleeman R,Van Wettum A,Trampert J,2006,Three-channel correlation analysis:a new technique to measure instrumental noise of digitizers and seismic sensors,Bull Seismol Soc Am,96(1),258-271.
Welch P, 1967,The use of fast Fourier transform for the estimation of power spectra:a method based on time averaging over short,modified periodograms,IEEE Trans Audio Electroacoustics,15(2),70-73.
Yuki Y,Ishihara Y,2002, Methods for maintaining the performance of STS-1 seismometer,Front Res Earth Evol,2,1-5.
(1)童汪练,2017,地震计自噪声测试《建标评估》初步探讨。
廖诗荣、陈绯雯,2008.应用概率密度函数方法自动处理地震台站勘选测试数据,华南地震,28(4),82-92.
Carter G, Knapp C,Nuttall A, 1973, Estimation of the magnitude-squared coherence function via overlapped fast Fourier transform processing,IEEE Trans Audio Electroacoustics,21(4),337-344.
Davis J P,Berger J,2007,Calibration of the global seismographic network using tides,Seismol Res Lett,78(4),454-459.
J R Evans,F Followill,C R Hutt, et al, 2010, Method for calculating self-noise spectra and operating ranges for seismographic inertial sensors and recorders,Seismol Res Lett,81(4),640-646.
Ekstrom G, Dalton C A, Nettles M, 2006, Observations of time-dependent errors in long-period instrument gain at global seismic stations,Seismol Res Lett,77(1),12-22.
Gerner A, Sleeman R, Lenhardt W,et al, 2016, Improving self-noise estimates of broadband seismometers by 3D trace rotation,Seismol Res Lett,88(1),96-103.
Holcomb L G,1989, A direct method for calculating instrument noise levels in side-by-side seismometer evaluations,Albuquerque,New Mexico:U.S. Geological Survey.
Holcomb L G, 1990, A numerical study of some potential sources of error in side-by-side seismometer evaluations, Albuquerque, New Mexico:U.S. Geological Survey.
Hutt C R, Evans J R, Followill F,et al,2010, Guidelines for standardized testing of broadband seismometers and accelerometers,Reston, Virginia:U.S. Geological Survey.
Li X J,Yang D K,Xie J B,et al,2015, Applicability of the Welch method for examining self-noise level parameters for broadband seismometers,Geodesy Geodyn,6(3),233-239.
Oppenheim A V,Schafer R W,Yuen C K,1978,Digital signal processing,IEEE Trans Syst,Man,Cybem,SMC-8(2),146.
Me Namara,D E,2004, Ambient Noise Levels in the Continental United States,Bull Seismol Soc Am,94(4),1517-1527.
Peterson J R, 1993, Observations and modeling of seismic background noise, U.S.Geological Survey Open File Report,94.
Ringler A T,Gee L S,Hutt C R,et al,2010a,Temporal variations in global seismic station ambient noise power levels,Seismol Res Lett,81(4),605-613.
Ringler A T,Hutt C R,2010b,Self-noise models of seismic instruments,Seismol Res Lett,81(6),972-983.
Ringler A T,Hutt C R,Evans J R, et al, 2011, A comparison of seismic instrument noise coherence analysis techniques, Bull Seismol Soc Am, 101(2),558-567.
Ringler A T,Sleeman R, Hutt C R, et al, 2014, Seismometer self-noise and measuring methods, In:Beer M, Kougioumtzoglou I,Patelli E,et al, Encyclopedia of Earthquake Engineering, Berlin, Heidelberg:Springer.
Sleeman R,Melichar P,2012, A PDF representation of the STS-2 self-noise obtained from one year of data recorded in the Conrad observatory,Austria,Bull Seismol Soc Am,102(2),587-597.
Sleeman R,Van Wettum A,Trampert J,2006,Three-channel correlation analysis:a new technique to measure instrumental noise of digitizers and seismic sensors,Bull Seismol Soc Am,96(1),258-271.
Welch P, 1967,The use of fast Fourier transform for the estimation of power spectra:a method based on time averaging over short,modified periodograms,IEEE Trans Audio Electroacoustics,15(2),70-73.
Yuki Y,Ishihara Y,2002, Methods for maintaining the performance of STS-1 seismometer,Front Res Earth Evol,2,1-5.
(1)童汪练,2017,地震计自噪声测试《建标评估》初步探讨。