Japan Median Tectonic Line

Japan Median Tectonic Line (中央構造線, Chūō Kōzō Sen^?), also Median Tectonic Line (MTL), is Japan's longest fault system. The MTL begins near Ibaraki Prefecture, where it connects with the Itoigawa-Shizuoka Tectonic Line (ISTL) and the Fossa Magna. It runs parallel to Japan's volcanic arc, passing through central Honshū to near Nagoya, through Mikawa Bay, then through the Inland Sea from the Kii Channel and Naruto Strait to Shikoku along the Sadamisaki Peninsula and the Bungo Channel and Hōyo Strait to Kyūshū.

The sense of motion on the MTL is right-lateral strike-slip, at a rate of about 5–10 mm/yr. This sense of motion is consistent with the direction of oblique convergence at the Nankai Trough. The rate of motion on the MTL is much less than the rate of convergence at the plate boundary, making it difficult to distinguish the motion on the MTL from interseismic elastic straining in GPS data.

The upper part of Japanese islands was created at the edge of Eurasian plate 180 million years ago.Then, 50 million years later, the lower part was created at the southern part of Yangtze continent. The lower part then rode on Izanagi plate and moved to the upper part. These islands were incorporated and formed the Japanese islands 70 million years ago. The boundary line between the upper part and lower part is the MTL.

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