Independent component analysis of geoelectric field data in the northern Nagano, Japan.
Independent component analysis of geoelectric field data in the northern Nagano, Japan.
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DOI：
10.2183/pjab.85.435
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Uyeda S
中科院分区：
文献类型：
--
作者：
Orihara Y;Kamogawa M;Nagao T;Uyeda S
1999年1月17日，日本长野县三个远距离台站同时观测到地电场异常变化。异常变化发生11天后，三个台站组成的三角形内的某处发生了4.8级主震震群。这种变化的形状是长方形的，就像希腊的货车式异常变化一样。这种异常可以被检测到，因为它发生在午夜，当时噪声水平很低。事实上，该地区曾发生过几次M4级地震，没有观察到之前的异常电性变化，可能是因为这些变化发生在嘈杂的白天。本文研究了用独立分量分析方法从含噪声的白天数据中提取1999年1月17日异常变化大小的信号的可能性。为此，在实际白天数据中嵌入了模拟噪声，这些数据不仅受到人为噪声的影响，而且还受到地磁扰动和降雨的影响。即使在地磁扰动或降雨影响较大的情况下，在所有情况下，至少有两个台站都能清楚地识别出异常变化。
Simultaneous anomalous change of geoelectric field was observed on January 17, 1999 at three far-distant stations in Nagano Prefecture, Japan. Eleven days after the anomalous change, an earthquake swarm with a M4.8 main shock started at a location within the triangle formed by the three stations. This change was rectangular in shape like the VAN-type anomalous change in Greece. The anomaly could be detected because it occurred at midnight when the noise level was low. In fact, there were a few M4-class earthquakes in the area for which no preceding anomalous electric changes were observed, perhaps because the changes occurred during the noisy daytime. In this paper, we examine if it is possible to extract the signal with the size of the anomalous change on January 17, 1999 from the noisy daytime data by Independent Component Analysis. For this purpose, a simulated noise was embedded in the real daytime data which were highly influenced by not only artificial noise but also by geomagnetic disturbances and rainfall. Even when the influence of geomagnetic disturbance or rainfall was large, the anomalous change was clearly recognized at least at two stations in all cases.
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影响因子：
5.4
作者：
Cardoso, JF;Laheld, BH
通讯作者：
Laheld, BH
DOI：
10.2183/pjab.78.179
发表时间：
2002-09-01
影响因子：
3.1
作者：
Tanbo, T;Nagao, T;Sakai, H
通讯作者：
Sakai, H
DOI：
10.1073/pnas.072208499
发表时间：
2002-05-28
影响因子：
11.1
作者：
Uyeda, S;Hayakawa, M;Tanaka, H
通讯作者：
Tanaka, H
DOI：
10.1073/pnas.97.9.4561
发表时间：
2000-04-25
影响因子：
11.1
作者：
Uyeda, S;Nagao, T;Takahashi, I
通讯作者：
Takahashi, I
影响因子：
2.9
作者：
VAROTSOS, P;ALEXOPOULOS, K
通讯作者：
ALEXOPOULOS, K