17:15 〜 18:45
[SEM12-P17] Analysis of the Network-MT data observed in the Shikoku-Chugoku Region of southwest Japan
キーワード：Network-MT法、地磁気地電流法、 周波数応答関数、電気比抵抗構造
The Philippine Sea plate subducts towards the Eurasian plate at the location of the Chugoku and Shikoku regions. The Median Tectonic Line of Japan also passes through the northern part of Shikoku region, and the geology of the Chugoku and Shikoku areas is complex. Shiozaki et al.(1998) pointed out the possible existence of a conductive layer in Chugoku region. Yamaguchi et al.(1999) concluded that the Shikoku region has a resistive area in the northern part of the region and high conductive area in the southern part. They also found a thin conductive layer on the subducting slab in the southern part of the median tectonic line.
We aim to estimate the three-dimensional electrical resistivity structure beneath the Chugoku and Shikoku regions using the Network-MT method. The Network-MT method is an electromagnetic exploration method that utilizes commercial telephone lines to measure voltage differences. Because the length of the measurement line is usually 10 to several tens of kilometers, we can measure relatively high signal-to-noise ratio data using this method, and the Network-MT data is little affected by galvanic distortion.
The data used in this study were observed from 1994 to 1996, with an average observation period of 90 days and a sampling interval of 10 s. We calculated data differences between two baselines to reduce the common artificial noises at central stations. In addition, we used only the night time data for the response function estimation. This presentation shows the characteristics of the estimated response functions in the Chugoku and Shikoku regions.
We aim to estimate the three-dimensional electrical resistivity structure beneath the Chugoku and Shikoku regions using the Network-MT method. The Network-MT method is an electromagnetic exploration method that utilizes commercial telephone lines to measure voltage differences. Because the length of the measurement line is usually 10 to several tens of kilometers, we can measure relatively high signal-to-noise ratio data using this method, and the Network-MT data is little affected by galvanic distortion.
The data used in this study were observed from 1994 to 1996, with an average observation period of 90 days and a sampling interval of 10 s. We calculated data differences between two baselines to reduce the common artificial noises at central stations. In addition, we used only the night time data for the response function estimation. This presentation shows the characteristics of the estimated response functions in the Chugoku and Shikoku regions.