is the largest crater lake in Honshū island, Japan. Located on the border between Aomori and Akita prefectures, it lies 400 meters (1,800 ft) above sea level and is 327 m (1,073 ft) deep, drained by the Oirase river. With a surface area of 61.1 km², Towada is Japan's 12th largest lake, its bright blue color is due to its great depth. The lake is roughly circular, with two peninsulas extending from its southern shore approximately one-third into the center of the lake. The lake is a popular tourist destination. Location Lake Towada is located approximately northeast of Tokyo, divided between the municipalities of Towada, Aomori and Kosaka, Akita. It forms part of the northern section of Towada-Hachimantai National Park Geology Lake Towada occupies the caldera of a stratovolcano still regarded as an active volcano. This volcano became active around 200,000 years ago, and through repeated eruptions and pyroclastic flows, especially 55,000 and 36,000 and 15,000 years ago, created an 11 kilometer diameter caldera with the proto-Lake Towada. From approximately 15,000 to 12,000 years ago, intermittent eruptions formed a small stratovolcano within this caldera (Mount Goshikiiwa). Intermediate eruptive activity continued and at least eight eruptions of magma occurred from 11,000 years ago to the present. The Ogurayama Lava Dome was formed approximately 7,600 years ago on the northeastern slope of the Goshikiiwa volcano. The Mikadoishi Lava Dome is estimated to be within 12,000 and 2,800 years ago. The collapse of these secondary lava domes approximately 5400 years ago give the lake its distinct shape and the inlet between its two peninsulas (called the “Nakaumi”) is the remnant of a secondary caldera which erupted and collapsed. Hydrology According to the National Institute for Environmental Studies of Japan, the water renewal cycle of Lake Towada is approximately 8.5 years. The catchment area of the lake covers an area of . The lake area is fed by around seventy rivers, half of which are intermittent. The Oirase River, which drains towards the Pacific ocean, is the only outlet. History The name of the lake is believed to derive from the Ainu word , literally meaning "rocky lake" According to a legendary account, the Yamata general Sakanoue Tamuramaro visited Lake Towada during one of his expeditions north to conquer the Emishi tribes, and built a small Shinto shrine on the eastern shore of the Nakayama peninsula in 807 AD dedicated to Yamato Takeru. The