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.

Source: Wikipedia — Japan Median Tectonic Line (CC BY-SA 4.0)