Episode 8: Jeju Volcanic Island and Lava Tubes

In 2007, scenic areas in Korea were designated as World Natural Heritage sites by UNESCO for the first time. The Mt. Halla Natural Reserve, the Geomunoreum Lava Tube System and the Seongsan Ilchulbong Tuff Cone were inscribed on the list under the title of “Jeju Volcanic Island and Lava Tubes.”
World Natural Heritage titles are given to areas of exceptional natural beauty or the sites of geological and ecological significance. UNESCO designated Jeju Volcanic Island and Lava Tubes as a World Natural Heritage site in recognition of the island’s well-preserved volcanic formations, including countless parasitic volcanoes and a world-renowned lava tube system.

“Seolmundae Granny, the daughter of the creator of this world, wished to create land on the vast ocean. So, the gigantic goddess collected soil from beneath the sea to create Jeju Island and carried soil in her skirt to build Mt. Halla. In the process, she dropped some soil, which formed small volcanic hills all over the island.”

The legend of Seolmundae Granny, the birth myth of Jeju Island, symbolically shows the process of the formation of the island that was created through the rise of magma from beneath the sea and numerous volcanic activities 1.8 million years ago.

360 big and small parasitic volcanoes, known as oreum in the Jeju dialect, stretch across the ground, while some 160 lava caves are scattered under the ground. The island itself is a volcano museum. Mt. Halla, among others, represents the volcanic island of Jeju.

“A high and flat mountain peak stands at the center of Tamra. With its sky-high peak, the mountain called Halla looks as though it could extend its hand into the Milky Way.”

As recorded in <Tamraji>, which is an encyclopedia of Jeju Island written by local official Lee Won-jin in 1653, Mt. Halla is situated at the center of the island. The large mountain, standing 1,950 meters high, was formed as a result of the collection of lava. Due to the blockage of the volcanic vent, water stayed at the summit to create a lake crater called “Baekrokdam.” In the southwestern part of the mountain, you can see strange rock formations and cliffs as well as about 40 oreum. The Mount Halla Natural Reserve, a UNESCO World Natural Heritage site, covers the area that is higher than 600 to 1,300 meters above sea level.
With a vertical distribution of different climate zones, the mountain is a rich habitat for a variety of plants and animals. The mountain’s unique ecosystem, along with its geological features, has gained international recognition.

The second site, the Geomunoreum Lava Tube System, shows a fascinating journey of volcanic activities. Located in Jocheon-eup in Jeju City, the Geomunoreum or parasitic volcano erupted dozens of times 300,000 years ago to form a vast crater. Lava from the volcano flowed 13 kilometers to reach the sea and resulted in the formation of some 20 lava caves, including Bengdwi Cave and Gimnyeong Cave. Manjang Cave is the biggest lava cave in Jeju.

“Boys, I can see the end of the cave. Follow me carefully so we can finish this expedition without any accidents.”
“Teacher, look at the wall over there. The cave definitely ends there, but it looks like there is a hole in that wall.”
“I’ll enter the hole to check it out. You wait here.”
“What’s in there?”
“It’s another cave. And it’s flat enough for a vehicle to pass.”

In 1946, an elementary school teacher and his students discovered Manjang Cave that stretches out as far as 7.4 kilometers. Another lava tube with geological value is Yongcheon Cave that was found in 2005. While the lava flow traces are seen on its wall, the cave also features characteristics of lime caves such as stalactites and stalagmites. It is a very rare cave, unprecedented in the world.

The third site is the Seongsan Ilchulbong Tuff Cone, which holds the secrets of the so-called hydro-volcano. Unlike other volcanoes in Jeju, it was formed by volcanic ash erupting from a shallow seabed between 40,000 and 120,000 years ago. At the summit of the 182-meter-high volcano, a large crater covering 21 hectares remains in its original state. Also, layers of volcanic sediment were formed on its sea cliffs. For these reasons, it is dubbed a “textbook of hydro-volcanoes.”
The Seongsan Ilchulbong Tuff Cone is very beautiful. It looks like a huge castle, as indicated in its name Seongsan, meaning “fortress mountain.” It also has a wonderful nickname “palace on the sea” as it provides a magnificent view of the sunrise. The word “Ilchulbong” refers to sunrise peak.

The Mount Halla Natural Reserve is an ecological treasure trove featuring volcanic splendors, while the Geomunoreum Lava Tube System shows various aspects of lava caves. And the Seongsan Ilchulbong Tuff Cone provides the best resource in the research of hydrovolcanic activities. Consisting of these three sites, Jeju Volcanic Island and Lava Tubes are invaluable natural properties that illustrate the process of volcanic formations on Earth.