ULF Electromagnetic Environment at Southern Boso Peninsula : Signal Discrimination of the Geoelectromagnetic Data

概要

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Geoelectrical and geomagnetic fluctuations are the end product of several geophysical phenomena. In particular signals measured in seismically active areas can be attributed to stress and strain changes associated with earthquakes. The complexity of the phenomena requires the development of advanced signal discrimintion and statistical methods. In this paper, we analyzed the short-term variability of geoelectrical potential and geomagnetic fields measured at Kiyosumi, Uchiura, and Fudago stations located in the southern part of Boso Peninsula, which is one of the most seismically active areas in Japan. The directions of signal arrival have been investigated with the use of local mid-night geoelectrical potential data, when artificial noise is low. Reduction of intense signals with external origin has also been made with the use of the interstation transfer function method. These analyses have shown the capability to discriminate the signal sources. Especially, direction finding analysis of time series data has shown to be effective in source separation. To identify the waveform and the direction of arrival of signals is important for monitoring the ULF electromagnetic environment in seismic areas and for understanding the preparation process of crustal activity.
社団法人電気学会の論文
2005-07-01