The Formation and Geographical Location of Jeju

Jeju Province, which forms a total area of 1,845 is made up of 8 inhabited isles and 54 uninhabited islets. It is at the eastern longitude of 12727E and the northern latitude of 3322N. The island is separated by the Jeju Channel, 59km in width, across from Haenamgot of the Haenam Peninsula, which is the southern most tip of the Korean peninsula. The nearest point in Japan from Jeju is Sasebo, at a distance of 250km. The nearest point in China is the mouth the Yangtze (in the Shanghai area). The distance, 420km, is nearly the same as that between Jeju and Seoul.

Jeju lies in the middle of the triangle which makes up the Korean Peninsula, the Japanese Islands and the Chinese continent. This ideal location has been advantageous for exchanging cultures and goods with these regions.

Jeju has been referred to as the smallest continent in the world due to the topography of Mt. Halla with big gentle slopes and the unique culture that the people of Jeju have created. Jeju was formed through volcanic activities. It is presumed that the ground was originally connected to the Korean Peninsula, rather than being isolated. It remained a continental island like a basin with a dry climate for some time when the volcanic activity started. Then the sea water rose when the volcanic eruptions became more active toward the end of the Ice Age, thus separating the land from the mainland and forming the present island.

It is believed that there had been four major, intermittent volcanic eruptions about 1.2 million years ago, based on the data from the craters, the formation of layers of the erupted material, the absolute age and the drilling of the deep spots. The first activity phase (1.2-0.7 million years ago) includes eruptions raging from basalt discovered in the seabed to trachyte. The seashore connecting Sanbangsan (Mountain) and the Wollabong was in a long oval shape. Sanbangsan (Mountain), Dragons Head, Gaksubawi(Rock) and Saejigi Oreum were created in this period. In the second phase (0.6 - 0.3 million years ago), the lava which contains underground water in Pyoseon-ri erupted and Manjanggul (Cave) was created, with the seashores similar to the present ones formed. The third phase (0.3 - 0.1 million years ago) saw the overall formation of Mt.Halla and the 500 General Rocks. The fourth phase (100 to 2.5 thousand years ago) created the ridges of Mt. Halla across the island with secondary volcanoes and completed the summit crater, Baengnokdam, toward the end of this phase, shaping the present topography of Jeju. Since volcanic activity continued until the eleventh century even after the creation of the parasitic cones, Mt. Halla is considered to be a dormant volcano rather than a dead one.