Ichinomegata Maar, Ninomegata Maar, and Sannomegata Maar make up the Oga-megata Maars. The only ones of their kind in the Tohoku Region, these freshwater lakes known as maars (crater lakes) provide water for the city of Oga. Ichinomegata Maar has a diameter of 600m, a depth of 44.6m, and is thought to have been formed about 60-80 thousand years ago. You can see peridotite which erupted from the depths of the earth, as well as layers of sedimentary rock called varve, making this important cultural asset world famous.
