| 应用主分量分析法研究唐山Ms7.8地震前的地磁异常 |
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| 引用本文： | 杜安娜,高惠璇.应用主分量分析法研究唐山Ms7.8地震前的地磁异常[J].地震,1995(3):291-297. |
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| 作者姓名： | 杜安娜 高惠璇 |
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| 作者单位： | 国家地震局分析预报中心
中国北京100036(杜安娜)，北京大学概率统计系 中国北京100871(高惠璇) |
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| 摘 要： | 应用主分量分析法对昌黎、青光、宝坻、红山等台站(1975—1977年)三年的每月五个静日地磁绝对磁场的资料及相应时间的太阳黑子相对数的资料进行计算。结果表明,第一主分量与太阳黑子相对数对应很好,相关系数为0.9以上,而第二主分量与太阳黑子相对数的相关系数为0.03左右。对于在某一固定频率而变化的地磁外源场,内外场的比例几乎恒定在一定水平上,而在唐山地震前内外场比值有明显的异常变化,笔者认为,这个恒定水平的偏离可能是由于地壳内应力不断积累导致的地下电导率的变化而引起的。用这种方法不仅可以消除地磁场的非局部变化,而且利用内外场比值的偏离或监视内场的变化可能为使用地磁场预报地震提供一个依据。
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| 关 键 词： | 地磁场 主分量分析 绝对磁场 地震前兆 |
STUDY ON GEOMAGNETIC ANOMALY BEFORE TANGSHAN EARTHQUAKE WITH M = 7.8 BY USING THE PRINCIPLE COMPONENT ANALYSIS |
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| Du Anna.STUDY ON GEOMAGNETIC ANOMALY BEFORE TANGSHAN EARTHQUAKE WITH M = 7.8 BY USING THE PRINCIPLE COMPONENT ANALYSIS[J].Earthquake,1995(3):291-297. |
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| Authors: | Du Anna |
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| Abstract: | The geomagnetic data ( 1975- 1977) of Changli, Qingguang, Baodi and Hongshan stations as well as the data of solar spot relative number ( 1975-1977) have been calculated by using the Principle Component Analysis.The results indicate that the correlative coefficient between the first component and the solar spot relative number is 0.95 and the second is 0.03. The ratio of internal and external field that the geomagnetic allogenic field variated with the fixed frequency is constant. But the ratio of internal and external field had an obvious anomalous variation before Tangshan earthquake, the authors consider that such a variation caused by the stress accumulation in the crust results in the conductivity changes and the variation of the internal geomagnetic field. This anomaly may be related with the Tangshan earthquake. However, the Hongshan station where is far from the epicenter of Tangshan earthquake, no similar anomaly of the ratio of internal and external field can be found.The non-local geomagnetic field can be not only eliminated by using this method, but also the ratio anomaly of internal and external field can be used for earthquake prediction. This method offers a new method for earthquake prediction. |
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| Keywords: | Geomagnetic field Anomaly Principle component analysis Absolute geomagnetic field Solar spot relative number |
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