SfondoRishiri volcano started erupting less than 200,000 years ago, building a stratovolcano and lava domes. Eruptions from the summit vents ceased about 37,000 years ago and since then, the only activity were sporadic eruptions from flank vents, forming scoria cones and maars along a 15-km-long NW-SE rift zone extending to the SE coast.
These flank eruptions were dominantly basaltic, but occasionally included more silica-rich magma including rhyolite. Large lava flows were erupted in the latest period of activity as well, and form most of the northern and western coast. (Smithsonian / GVP volcano information)
See also: Sentinel hub | Landsat 8