Global Volcanism Program | Image GVP-05602
Rishiri is a highly eroded edifice forming an island off the NW tip of Hokkaido. The main edifice contains scoria cones on the flanks, with a maar containing this lake on the lower S flank. It was constructed during the Pleistocene and scoria cones and the maars on the lower flanks erupted 30,000-8,000 years ago.
Photo by Yoshihiro Ishizuka, 1993 (Hokkaido University).