Preseismic anomalous telluric current signals observed in Kozu-shima Island, Japan
Preseismic anomalous telluric current signals observed in Kozu-shima Island, Japan
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DOI：
10.1073/pnas.1215669109
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发表时间：
2012-11-20
影响因子：
11.1
通讯作者：
Uyeda, Seiya
中科院分区：
文献类型：
--
作者：
Orihara, Yoshiaki;Kamogawa, Masashi;Uyeda, Seiya
1997年5月14日至2000年6月25日，在东京以南约170公里的小津岛进行了地电流监测，这实际上是地电位差的同义词。在监测期间，观察到19个异常地电流变化（ATC）。通过假设不同震级和震源距离范围的不同提前时间，对它们与附近地震的可能相关性进行了统计研究。最好的相关性可能是震级大于3.0的地震发生在20公里的震源距离内。有23次这样的地震，其中11次在30天内发生了ATC。在这11次地震中，前5次和前6次ATC分别为大地电流的正极性和负极性。它们的震中在空间上很好地聚集在该岛的东部和西部。这些事实显然超出了偶然的预期，并导致了一个简单的推测模型。
Monitoring of telluric current, which is practically a synonym for geoelectric potential difference, was conducted on Kozu-shima Island about 170 km south of Tokyo from May 14, 1997 to June 25, 2000. During the monitoring period, 19 anomalous telluric current changes (ATCs) were observed. Their possible correlation with nearby earthquakes was statistically examined by assuming various lead times for different ranges of magnitude and focal distance. The best correlation may be obtained for earthquakes with a magnitude greater than 3.0 occurring within 20 km of focal distance. There were 23 such earthquakes, of which 11 were preceded by ATCs within 30 d. Of these 11 earthquakes, preceding ATCs of 5 and 6 were positive and negative polarities of telluric current, respectively. Their epicenters were spatially well clustered in the east and west of the island. These facts were clearly beyond those expected by chance and led to a simple speculative model.