Ichinome Lagoon

Along with the Ninome Lagoon and the SannomeLagoon, it is a rare volcanic lake in the world called Maar (a lake formed by groundwater accumulating in an explosion crater after an eruption).
It is still used as a water source in the surrounding area.
The lake can be overlooked from the Hachibotai, behind Toga Bay. (Maximum depth: 42.0m / diameter: 600m)
Tens of thousands of years' worth of strata accumulated every year on the bottom of Ichinome Lagoon.
By analyzing these annual stripes, which are said to be found only in a few places in the world, it is possible to read the changes in climate and environment from year to year, and has attracted attention as a valuable academic resource.
Ichinome Lagoon was designated as a national monument in July 2007, and Sannome Lagoon was designated as a prefectural monument in March 2010.