地震研究

对上海崇明长江农场井深约460 m的深井综合地震观测系统中的地磁观测数据进行质量分析。通过对该系统2套地磁仪以及相距约12 km的三烈中学台地磁仪的时序图、相关性、频谱以及等效背景噪声水平对比分析,得出:(1)上海深井综合地震观测系统中用膨胀水泥固定在井深约460 m岩石中的地磁仪工作正常,未受同一耐压腔体内应变仪、地温计、空隙压计传感器和安装在同一个钻孔内深度为430 m左右的地震仪、倾斜仪传感器和系统影响,且相距60 m远的长约400 m的井下套管对其相对变化也未产生扰动;(2)长江农场深井地磁观测的等效背景噪声水平明显小于三烈中学台,开展深井地磁观测既能节约经费又能获得高于地表的观测数据质量,是值得推广的建设方式。

We mainly analyzed the quality of geomagnetic observation data recorded by comprehensive seismic observation system which were installed at the depth of 460 m in deep borehole on Changjiang farm in Shanghai.Then we did a comparative analysis of sequence diagram,correlation,frequency spectrum and equivalent background noise of geomagnetic observation data recorded by magnetometers in Changjiang Farm Station(CJNC)and Sanlie Middle School Station(SLZX)which is 12 m apart from the CJNC Station.The result shows that:(1)The magnetometer was installed in well depth of 460 m by expanding cement works normally in the deep borehole comprehensive seismic observation system,and it doesn't interfered not only by the strain meter,geothermometer,pore pressure meter which were installed in the same withstand voltage chamber,but also by the seismometer,tilt meter which were installed at depth of 430 m in the borehole,and it doesn't interfered by downhole casing with 400 m long at a distance of 60 m.(2)The equivalent background noise of geomagnetic observation data in deep borehole on Changjiang farm is obvious less than that in the surface observation of Sanlie Middle School.Geomagnetic observation in deep borehole not only can save outlay but also can obtain higher quality observation data than the surface observation,so it is worth popularizing.

引言
1 资料和方案
2 研究方法
3 结果分析
4 结论和讨论

表1 CJNC台和SLZX台相关系数统计表<br/>Tab.1 Correlation coefficients statistic of CJNC and SLZX stations

表1 CJNC台和SLZX台相关系数统计表
Tab.1 Correlation coefficients statistic of CJNC and SLZX stations

图1 2011年7月1~30日CNJC台和SLZX台地磁各分量小时值时序图<br/>Fig.1 Hour time sequences of each geomagnetic components recorded by CNJC and SLZX Stations from Jul.1 to 30,2011

图1 2011年7月1~30日CNJC台和SLZX台地磁各分量小时值时序图
Fig.1 Hour time sequences of each geomagnetic components recorded by CNJC and SLZX Stations from Jul.1 to 30,2011

图2 2011年7月2日CNJC台和SLZX台地磁各分量秒值时序图<br/>Fig.2 Second sequences of each geomagnetic components recorded by CNJC and SLZX Stations on Jul.2,2011

图2 2011年7月2日CNJC台和SLZX台地磁各分量秒值时序图
Fig.2 Second sequences of each geomagnetic components recorded by CNJC and SLZX Stations on Jul.2,2011

图3 CJNC1台和SLZX台地磁各分量小时值频谱分析结果(Z:垂直分向; D:磁偏角; F:地磁总强)<br/>Fig.3 Frequency spectrum of hour time of each geomagnetic components recorded by CJNC1 and SLZX Stations

图3 CJNC1台和SLZX台地磁各分量小时值频谱分析结果(Z:垂直分向; D:磁偏角; F:地磁总强)
Fig.3 Frequency spectrum of hour time of each geomagnetic components recorded by CJNC1 and SLZX Stations

图4 CNJC1台水平分量H的信号分离过程图<br/>(截取周期:<5 s)<br/>(a)原始信号;(b)分离出的周期小于5 s的高频成<br/>分时序图;(c)周期大于5 s低频成分时序图<br/>Fig.4 Separate process of H component recorded by CJNC1 Station(intercepted period is less than 5 seconds)(a)original signal;(b)separated time series including high frequency component with the period is less than 5 seconds; (c)time series including low frequency component with the period is more than 5 seconds

图4 CNJC1台水平分量H的信号分离过程图
(截取周期:<5 s)
(a)原始信号;(b)分离出的周期小于5 s的高频成
分时序图;(c)周期大于5 s低频成分时序图
Fig.4 Separate process of H component recorded by CJNC1 Station(intercepted period is less than 5 seconds)(a)original signal;(b)separated time series including high frequency component with the period is less than 5 seconds; (c)time series including low frequency component with the period is more than 5 seconds

图5 SLZX台水平分量H的滤信号分离过程<br/>(截取周期:<5 s)<br/>(a)原始信号;(b)分离出的周期小于5 s的高频成分<br/>时序图;(c)周期大于5 s低频成分时序图<br/>Fig.5 Separate process of H component recorded by SLZX Station(intercepted period is less than 5 seconds)(a)original signal;(b)separated time series including high frequency component with the period is less than 5 seconds; (c)time series including low frequency component with the period is more than 5 seconds

图5 SLZX台水平分量H的滤信号分离过程
(截取周期:<5 s)
(a)原始信号;(b)分离出的周期小于5 s的高频成分
时序图;(c)周期大于5 s低频成分时序图
Fig.5 Separate process of H component recorded by SLZX Station(intercepted period is less than 5 seconds)(a)original signal;(b)separated time series including high frequency component with the period is less than 5 seconds; (c)time series including low frequency component with the period is more than 5 seconds

图6 地磁仪RMS值和截取频率关系图<br/>(a)水平分量;(b)垂直分量;(c)磁偏角分量<br/>Fig.6 Relation between intercepted frequency and RMS of magnetograph(a)H component;(b)Z component;(c)D component

图6 地磁仪RMS值和截取频率关系图
(a)水平分量;(b)垂直分量;(c)磁偏角分量
Fig.6 Relation between intercepted frequency and RMS of magnetograph(a)H component;(b)Z component;(c)D component

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引言

1 资料和方案

2 研究方法

3 结果分析

4 结论和讨论

期刊信息