Main theme of the Izu Peninsula Geopark

Volcano gifts from the south

Izu Peninsula is a land giving a unique insight into the history of our earth. Previously a submarine volcano and then a volcanic island, the peninsula has been shaped through a number of geological events taking place across huge spatial and temporal scales–starting with its collision with the Honshu, and followed by volcanic activities and crustal movement that are continuing right up to the present day, enabling the visitors to learn about the history as well as the blessings of our earth.

To symbolize this unique history of Izu Peninsula and its present physical geography, “Volcano gifts from the south” has been chosen as the main theme of the Izu Peninsula Geopark Project and it is subdivided into the following five sub themes: (1) A volcanic massif drifted from the south and collided with the Japanese mainland; (2) Geological basement originated from submarine volcanoes; (3) Large terrestrial volcanoes after the collision; (4) Izu peninsula is alive; (5) Unique local culture developed by the geological benefits, and people’s wisdom over a geological disaster.

History of Izu Peninsula

Judging from strata and other evidence, the history of Izu Peninsula can be traced to approximately 20 million years ago.

About 20 million years ago, Izu was a group of submarine volcanoes located several hundreds of kilometers south from Honshu, the main island of Japan.

Submarine volcanoes and volcanic islands that gradually moved north together with the plate itself and eventually collided with Honshu–forming the present day peninsula. This happened approximately 600,000 years ago.

A phase of composite terrestrial volcanism followed and continued till approximately 200,000 years ago. Large volcanoes like the Amagi Volcano and the Daruma Volcano formed during this phase. 

After the volcanic activity of these large terrestrial volcanoes came to an end,  groups of small monogenetic volcanoes that erupt only once began their activity. This phase of volcanism still continues, making Izu a rare example of an active monogenetic volcanic field–called the Izu Tobu Volcano Group.

As the Philippine Sea Plate is still continually pushing up Izu into Honshu, this ongoing process creates various landforms and dynamic landscapes.

Such unique geological history and land formation activities at multiple scales make Izu a one of its kind land, a ‘living peninsula’ created out of the ongoing collision between two island arcs — which cannot be found anywhere else in the world.