A newly found cave, tentatively named Woljeong Namjimidonggul, on Jeju Island. It is believed to be a part of the Geomunoreum and Lava Tube System, a UNESCO-designated World Natural Heritage . / Yonhap

By Kim Rahn
Staff Reporter

A cave has been discovered on Jeju Island, near a system of lava tubes and other volcanic topography that has already been designated as a World Natural Heritage Site by UNESCO.

The cave was found in Woljeong-ri, Jeju City, near Dangcheomul-donggul, one of five lava tube caves in the heritage site of the Geomunoreum Lava Tube System, according to the World Natural Heritage Jeju, Tuesday.

The heritage authorities have been conducting a drilling operation near the system since April to determine whether there are more undiscovered caves.

The cave, tentatively named ``Woljeong Namjimi-donggul,'' is 40 to 60 meters away from Dangcheomul-donggul, measuring more than 100 meters long, five meters wide and 1.5 to 2 meters tall. The ceiling of the cave is about 3.5 meters below ground level.

After lava formed the cave, carbonates from the surface were dissolved by rain and flowed down to the cave, creating carbonate products, experts said.

``Cave products such as stalactites, stalagmites, stone pillars and cave corals, are well preserved in the cave, presenting a beautiful view,'' said an official of World Natural Heritage Jeju.

Through the drilling operation, the authorities also found that Yongcheon-donggul, which was previously presumed to be about 50 meters away from Dangcheomul-donggul, was just 3 to 10 meters away. ``It was also found that the new cave runs parallel with Yongcheon-donggul. The chances are now higher that more undiscovered caves may exist near Yongcheon-donggul in the same direction,'' he said.

``The cave was the first of its kind to be found through a probe, while others were discovered accidentally. We will conduct additional drilling together with the Cultural Heritage Administration after probing the area with ground penetrating radar,'' the official said.

The lava from Geomunoreum, a volcanic cone, near Jeju City flowed in a northeast direction down to the coastline for about 13 kilometers between 100,000 and 300,000 years ago.

Besides the new cave, the lava tube system includes Bengduigul, Manjanggul, Gimnyeonggul, Yongcheon-donggul and Dangcheomul-donggul. The system, Mt. Halla and Seongsan Ilchulbong (Sunrise Peak) Tuff Cone were designated World Natural Heritage sites in 2007.

rahnita@koreatimes.co.kr