noun
Itoigawa-Shizuoka Tectonic Line
A major geological fault line in Japan, often abbreviated as ISTL. Used in geology and geography contexts.
糸魚川静岡構造線は、日本列島を東西に分ける大断層です。
The Itoigawa-Shizuoka Tectonic Line is a major fault that divides the Japanese archipelago into east and west.
Fossa Magna is the larger geological zone, while the Itoigawa-Shizuoka Tectonic Line is its western boundary.
Named after the cities of Itoigawa (Niigata) and Shizuoka, which mark the endpoints of this tectonic line.