Geo-historical scheme

Isolation from the Continent: The formation of Japanese island arc

Let me remind you how the Japanese Island Arc was developed so that you are able to understand that the specific evolutional history of the Izu Peninsula. The Japanese Island Arc extends similar with boomerang-shape. The center of the “Boomerang” may locate at Tokyo area. The arc seems to be bending, do you know why?

Former Japanese Island Arc had attached to the east edge of the Eurasian Continent at the time of the Cretaceous when dinosaurs were alive. As time goes by, volcanic activities became severe due to the subduction of the oceanic plate ca. 25 Ma before, and then the edge of the continent started to apart. A mediterranean sea developed between the continent and the island arc, and the sea became the Sea of Japan. The arc separated into two blocks and rotated similar with opening door. Finally, the arc settled at the position same as today ca. 14 Ma before. At this time, the Izu block located far away from the Island Arc.

The Izu Peninsula has an unique geological scheme other than the mainland of Japan.

Geological history of the Izu Peninsula is able to date back ca. 20 Ma before.
In the initial of the Izu Peninsula, it located at about 800 km south, nearby the tropic of Cancer. At that time, Izu was volcanic groups at the deep sea ocean. The Pacific plate subducts under the Philippine Sea plate, and this subduction supplies magma which requires to develop the Izu Peninsula. On the other hand, the Philippine Sea plate subducts under the Eurasian plate on which the mainland of Japan puts. Submarine volcanos and volcanic islands drifted due to northward shift of the Philippine Sea plate. Finally the block was collided with the mainland, and it formed the peninsula same as today ca. 600 ka before.

Since the formation of the peninsula till 200 ka before, volcanic erupted almost the whole of the peninsula and large scale terrestrial volcanoes had formed that we are able to see in the peninsula today.

In the eastern part of the peninsula, the independent monogenetic volcanoes of the Izu Tobu volcano group eruption continued until today. Continuous movement of the Philippine Sea plate cause the crustal shorting causes the collision orogeny and volcanisms as well as faulting activities. These geological characteristics forms the sceneries and landscape of the Izu Peninsula. Then the Izu Peninsula is the only place in the world that two active volcanic arcs meet.

Nature of the Peninsula

Topography

The Izu peninsula extends about 60 km southward from the central part of the mainland of Japan. It has a maximum east-west width of 40 km, and a total coastal length of 318 km. Most of the area is covered by moderate mountains. The highest peak is Mt. Banzaburo (1405 m asl) in the Amagi Mountains. The protrusion of these mountains causes heavy rain. This complex landscape also develops scenic diversity between and within areas.
Sagami bay, located to the east of the peninsula, has a depth of 1000~1500m off the shore. Suruga bay in the west is still deeper, 2500m in the baymouth between Irozaki and Omaezaki. These deep bays are influenced by water coming in from outlying oceanic systems.
The Kanogawa River is the longest river of the peninsula (46 km length). In the lower parts of the Kano plain, the width of the river narrows due to the inflow of volcanic ejecta and debris flow, and it tends to flood during heavy rain and typhoons. The peninsula poorly develops large river systems except the Kanogawa river. The deep waters near the coast and different temperature ranges and water qualities in the bays make these water bodies rich fishing grounds.

Climate

According to the Köppen-Geiger classification, the Izu peninsula is located in the temperate humid climate zone, as with most locations in Japan. However, the climate within the peninsula varies appreciably between the coastal and interior parts. The coastal regions are influenced by the warm Kuroshio current and have a mean annual temperature of 15–17 ºC; the southern tip of Irozaki Cape does not receive any snowfall even in the winter. In contrast the northern Tagata plain has a wide difference between day and night temperatures, and winter in this area is noticeably colder. The central Amagi highland receives a flow of humid air from the Pacific, resulting in high levels of precipitation (over 4000 mm/year at Mt Amagi) and frequent snowfall during winter. On the other hand the western part of the peninsula is relatively dry due to the prevailing winds depositing their moisture content over the central highlands. Compared to the Tokyo metropolitan area, the coastal areas are warm in winter and cool in summer.

Ecosystems and Biodiversity

The climatic diversity of the peninsula directly contributes to its biodiversity. The Amagi Mountains is known for its forests of deciduous broadleaf trees such as Japanese Beech and Aceraceae family. In particular, it is unusual to find a Fagus crenata forest on the Pacific coast. A diverse range of marine organisms, mostly native to a warm marine environment, can be found in the sea around the peninsula. The Japanese Spider Crab is the largest crab species in the world, and it lives in the deep Suruga bay to the west of Izu.

The Izu Peninsula Geopark and Tourism Bureau

The new managing entity of the Izu Peninsula Geopark.

The Izu Peninsula UGGp has greatly strengthened its managing entity on the occasion of the ten-year anniversary of its establishment.

First, the new entity has earned a juridical personality under the domestic legal system. The previous organization—the Izu Peninsula Geopark Promotion Council—was legally considered a “volunteer group”. The consolidation of the Tourism Bureau, which had already acquired a legal personality, and the Geopark Council into one entity was primarily aimed at surmounting the drawbacks of the latter.

The establishment of the new entity advances the long-standing aspirations of the local populace. The former Tourism Bureau, which used to be known as the “Creation Centre”, had been originally established as a flagship institute to lay down a holistic strategy to revitalize the regional economy and strengthen its civil society. However, the organization could not fulfil this mission and gradually narrowed its scope to tourism promotion; later, it was renamed the Izu Peninsula Tourism Bureau. Its merger with the Geopark Promotion Council decisively revived the initial idealism of the organization. The greater bureau will contribute to the tenets of the Global Geopark Network and introduce sustainability to the tourism sector of the peninsula. This endeavor has the support of all the mayors in this region.

In addition, the consolidation has tremendously strengthened our competence in terms of marketing and promotion. The Chief Operational Officer of the former tourism bureau, who has four decades of experience running a private tourism agency, has been actively engaged in the promotion of Geo-tourism since the launch of the new entity. The network of the tourism bureau is widely extended to include the private sector. This network is undeniably beneficial to the endeavors of our new entity.

Executive Board and Steering Committee

The responsibility for strategic decision-making at the greater bureau rests with the Executive Board and the Steering Committee. The vast majority of their members—including mayors of local governments—overlaps with the members of equivalent boards from the previous entity. Therefore, consistency in the policies is ensured. Furthermore, to avoid unnecessary complications in the decision-making process, the same boards govern both the tourism and regional revitalization sections.

The President of the former entity—the Mayor of Izu City—remains a member of the Executive Board and will serve as the Chairperson of the new Geopark Council. In addition, the former academic advisor and the Chairperson of the Geo-guide association were appointed as members of the Executive Board as a sign of our indissoluble commitment to the vision and mission of the former entity. Their appointment will also enable the tourism sector in the region to become more sustainable.

Geopark Promotion Council and the Board of Delegations

While the Geopark secretariat endeavors to strengthen its governance and financial status, the Geopark Council proudly retains the grass-roots features of the previous entity. Our commitment towards bottom-up decision making is resolute, as our geopark has its origin in an enthusiastic two-decade long civil movement aimed at establishing a global geopark.

To ensure wide participation of the members of the movement, their delegates will deliberate on proposals from the secretariat. Representatives of the Board of Education of the local governments have also joined the delegation meeting since the vision of the Global Geopark Network further prevails into this region.

Working Group

When it is deemed necessary, the council may organize working groups to address specific issues pertaining to the operation of the geopark. As of June 2022, the council envisions launching a working group to lay down a mid-term strategy for promotion of the education for sustainable development and another group to accelerate implementation of the existing educational programs in local schools.

Geo-supporter

Geo-supporters are individuals with an interest in the Geopark. Every month, the Promotion Council and the Geo-guide association send a newsletter about “Next Month’s Geo Events” to all geo-supporters, and also sends email notifications of things that are likely to be of interest as they come up. We gave complimentary gifts to reward supporters who frequently join these events of the supporters by complimentary gifts. In addition, we highlight their enthusiastic and distinctive activities through press releases and the Geopark website. Any individual is eligible to join and just petty one- shot registration fee is charged.  Become a registered supporter