Depth of Lake Tazawa below Sea Level (Cryptodepression)
Lake Tazawa is the deepest lake in Japan at 423.4 meters. With its surface elevation of 249 meters, it is 174 meters below sea level (the depth of crypto-depression) and the deepest in Japan in this regard too. The second deepest crypto-depression is in Lake Ikeda (167 meters), the third in Lake Shikotsu (117 meters), and the fourth in Lake Toya (96 meters). Lake Tazawa is a typical caldera lake, which was created by the eruption of a magma chamber and the subsequent massive subsidence during the formation of the Japanese Archipelago when the sea floor rose to form islands and mountains. Because of its depth and the circulation of water probably due to warm spring water, the lake never freezes in winter.