Exploring Vietnam’s first-ever volcanic cave system, including SE Asia's longest grotto

A member of Vietnam’s travel agent association has told Tuoi Tre (Youth) about his eye-opening experience exploring the country’s first-ever volcanic cave system, one part of which is considered the longest such feature in Southeast Asia.

Tran The Dung, of the Vietnam Society of Travel Agents (VISTA) and director of a local travel firm, recently took an expedition to the country’s newly discovered volcanic cave system.

The system, located in Krong No District of Dak Nong Province in the Central Highlands, consists of 12 caves.

One of them – C7 – is 1,055 meters long, and a group of Japanese scientists who helped discover the system said it is the longest volcanic cave in Southeast Asia, adding that some parts of this cave cover thousands of square meters.

The path leading to Cave C9. Photo: Tran The Dung

Taxing yet rewarding experience

In Dung’s recount, he and his team left Draysap Waterfall Tourism Complex, rode along Provincial Highway 684 which leads to Krong No District, and crossed a 20-kilometer stretch of dusty paths and steep cliffs before reaching Chu B’luk Volcano.

The volcano stands out amidst the vast, deserted hilly area in Buon Choah Commune.

Visitors have to trek through a two-kilometer stretch of bumpy rocky surface and small hills of basalt rocks, which were formed by lava during eruptions countless years ago, Dung said.

He and his teammates sometimes ate ripe tiny tomatoes from bushes on the way.

The vegetables partly quenched their thirst and refreshed them from the scorching heat.

The entrance to Cave C9. Photo: Tran The Dung

Eventually, Dung and his teammates finally set foot on the peak, which is 593 meters above sea level. They were overwhelmed at its awe-inspiring conical crater.

They then stumbled along the cliffs to get to the bottom, where it was pitch black and utterly tranquil.

Resplendent blocks of basalt rocks gradually unfolded in an area spanning roughly 100 square meters.

Dung revealed that standing atop Chu B’luk Volcano, a click at a hand-held GPS device can pinpoint the spectacular cave system, which was formed by lava currents during volcanic eruptions many years ago.

The currents give rise to countless grottos that stretch some 25 kilometers. Most lava caves are cylindrical and boast unique charms, Dung noted.

A gas pit in Cave C6. Photo: Tran The Dung

While Cave A1 is known for its numerous twists and turns, the entrance to Cave C9 – the cave nearest to the volcano – stands some 530 meters from sea level.

Cave C9 is also the tallest in the system.

The 200m-long cave splashes in ample sunshine and utter darkness and boasts visually striking cliffs.

Meanwhile, Cave C6, which received a team of Japanese experts earlier this month, have unique charms.

This is one of the few caves with a natural gas pit formed from masses of gas emitted during previous eruptions, Dung observed.

Sun beams leak through the pit, dancing on the cliffs.

An explorer is seen getting ready to climb down Cave C7. Photo: Tran The Dung

Dung added the highlight of his group’s strenuous three-day trek in the area was Cave C7, which measures 1,066.5 meters and has been recognized as Southeast Asia’s longest and most spectacular.

The cave remains relatively pristine as few have explored it due to treacherous terrain.

“Upon approaching Cave C7, I was instantly held in awe by the shape of its entrance. Unlike other caves, the entrance to Cave C7 is round and level and looks just like a crater. Around 10 meters toward its bottom is a luxuriant layer of ferns and forest vegetation,” Dung described.

However, the only way to explore the cave is by climbing down a small rope ladder.

The entrance to Cave C7 resembles a crater when seen from below. Photo: Tran The Dung

“Many in our group marveled at the grandeur of Cave C3, which measures 594.4 meters in length and ranks as Southeast Asia’s second longest. However, Cave C7’s unrivalled resplendence far surpasses that of Cave C3,” he noted.

Located roughly 5,030 meters from Chu B’luk Volcano and some 428 meters above sea level, Cave C7 encompasses uniquely staggering features, ranging from its length, vastness and the shape of its entrance, strata of rock formed from solidified lava, and its surface, which strongly resembles currents of lava, to gas pits and lush vegetation.

“The volcanic cave system boasts beyond-compare resplendence, and really needs to be preserved like an outdoor museum. As a result, tourist activity is yet to be encouraged while we’re waiting for the area to be zoned,” said La The Phuc, director of the Vietnam Geology and Minerals Museum in Hanoi.

Cave C7 nestles some 20 meters under the ground. Photo: Tran The Dung

The discovery of the volcanic system was announced in late December by experts from the General Department of Geology and Minerals of Vietnam and the Japan Caving Association (JCA) after seven years of research.

In 2007, scientists from the general department detected some volcanic caves in Krong No District and JCA experts have since joined their Vietnamese counterparts in further explorations.

The system, which is a unique natural heritage of the volcanic eruption process that took place millions of years ago, is the first to have been discovered in Vietnam.

It includes 12 volcanic caves, three of which have been measured in detail.

Vestiges of lava inside Cave C7. Photo: Tran The Dung

The discovery will be of great significance to international geological and archeological studies, as very few places in the world have such a system of volcanic caves and craters as that in Krong No, experts said.

Dr. Hiroshi Tachihara, honorary president of the JCA, who has explored caves for the past 40 years, told a previous press conference that five of Southeast Asia’s six longest volcanic caves belong to the volcanic cave system that has just been found in Vietnam.

Strata of solidified lava rock are seen inside Cave C7. Photo: Tran The Dung

Dak Nong authorities are conceiving a project to build a geological park (geopark) that houses the 12 volcanic caves, with a view to obtaining UNESCO recognition of the place as a global geopark in the future, a senior official said following its discovery.

The project will be submitted to the Prime Minister and relevant agencies for consideration, the official said, adding that their most important plan is to introduce the park to UNESCO and earn its recognition.

The JCA exploration team, which is credited with measuring, researching, and helping announce the discovery of the volcanic system, returned to the site for a week-long expedition earlier this month for further research.