Lake Unagi is a Japanese maar lake associated with an eruptive vent line extending towards the sea from the parent volcano Ikeda Caldera which contains Lake Ikeda.
The large lake in the foreground is Lake Ikeda but beyond it to the east (left of picture) is Lake Unagi with Cape Sata in the far distance over the waters at the head of Kagoshima Bay. The volcanic cone to the right of the picture is Mount Kaimon.