|▲ Manjanggul cave contains a large underground lake, not accessible to the public.Scientists have yet to study the entire depth and breadth of the Jeju lave tube system. Photos courtesy Jeju Cave Research Institute|
At the heart of Jeju island is the famous Hallasan, from which all the island was formed. Approximately two million years ago this tiny island began its life as a volcano, spewing lava from its summit and forming an island with an extraordinary physiography, and in the process, creating one of the most extensive and well-preserved cave systems in the world.
One of Jeju's largest features is its parasitic cones, known as oreums. More than 360 of these satellite volcanoes cover the surface of the island, but what's underneath them is even more interesting: a system of lava tubes formed over a period of more than 100,000 years. The Geomunoreum lava tube system is among the greatest of its kind in the world, with varicolored walls and carbonate deposits along its structure. To really experience Jeju, you have to go underground.
Manjanggul cave perhaps longest in world
The most well known and extensive cave is the Majang cave, or Manjanggul. Its official length has been contested by numerous sources, and is argued as possibly the longest cave in the world. However, at present, it is estimated to be somewhere between 7,416 and 13,422 meters. Only the first kilometer of the cave is open to the public, leaving most of its structure and mystery preserved.
The cave hosts many wonders, including unique lava pillars, distorted walls, and molten shapes formed by the lava. There are also dozens of unique cave creatures found within Manjanggul, including several fascinating bat species. Over 100 different species have been found in the caves in Jeju.
Other significant lava caves in Jeju include Bengdwigul, Gimnyeonggul, Dangcheomuldonggul, and the more recently discovered Yongcheondonggul, providing a large number and wide selection of cave types for scientific study. While Jeju island is mostly comprised of basalt and lava, large limestone deposits have also been discovered in the caves, possibly created by droplets of calcium carbon trioxide from tree roots penetrating the upper layers of the rock.
Yongcheondonggul, or Yongcheon Cave, boasts an impressive underground lake, while Bengdwigul contains one of the most complex and mazelike cave systems on the planet. Dangcheonmuldonggul is a lot smaller than either, but has a breathtaking display of carbonate and limestone formations.
Caves listed as World Natural Heritage Sites
Along with Seongsan Ilchulbong and Hallasan, the Geomunoreum lava tube system was designated as a World Natural Heritage Site by the United Nations Educational, Scientific and Cultural Organization (UNESCO) back in 2007, and are the only natural sites in Korea found on the UNESCO list.
To be considered a UNESCO World Natural Heritage Site, a natural site must meet several criteria. A few of which are to “be outstanding examples representing major stages of the earth's history... have significant ongoing geological processes in the development of landforms, or significant geomorphic or physiographic features” and “contain superlative natural phenomena or areas of exceptional natural beauty and aesthetic importance,” according to UNESCO guidelines.
Founded in 1945, UNESCO was established to promote international co-operation in the fields of science, education, communication, and culture among its member and associate member states. The Republic of Korea joined UNESCO back in 1950, and since then has had many cultural and some natural sites recognized by the organization. This has resulted in increased tourism and traffic through its sites.
This brings up one of the most important issues to the sites on Jeju, particularly for the caves. Currently, the management of these sites has a plan in place for the increase in traffic to avoid any potential damage caused by it. There are future plans to extend the public sectors to include even more of the significant lava tube systems.
All over this island are many caves, each telling a different story. Whether it appeals to your scientific or aesthetic eye, these caves are a wonderous world treasure.
ⓒ Jeju Weekly 2009 (http://www.jejuweekly.com)