After Izu reached its present shape of a peninsula and up to approximately 200,000 years ago, a number of terrestrial volcanic eruptions occurred all around the area, resulting in the formation of Amagi Volcano, Daruma Volcano, and other massive volcanoes, which make up the framework of Izu Peninsula as it is today.
After the volcanic activity of these large terrestrial volcanoes comes to an end, monogenetic volcano fields which are quite rare in Japan become active, and the area is now renowned as one of such active volcano fields called the Izu Tobu Volcano Group. The plate is still in motion continually pushing the land of Izu into Honshu, creating various landforms with its crustal movement.