Jomblang is one of hundreds of cave complex in Gunungkidul that becomes well known because of its uniqueness. In 2011, it is used as the object of a program called Amazing Race America. Located on the range of karst hills in the southern coastal spread along Gombong, Central Java up to karst area in Sewu Mountain, Pacitan, East Java, this vertical cave has collapse doline. It was constructed from a geological process when the land and its vegetation vanished into the bowel of the earth thousand years ago. The ruins formed a sinkhole, which in Javanese language was called sumuran or luweng. As a result, the cave which has 50 meter diameter was later named Luweng Jomblang.
To enter Jomblang cave, we need to master single rope technique (SRT). Everyone who wish to do caving in this place should use special equipments based on the caving safety standard in a vertical cave and should also be accompanied by the experienced caving trainers. After wearing coverall, boot, helmet, and headlamp, a trainer set SRT set on our body while explaining the name of each tool and its function. The single rope technique equipments consisted of seat harness, chest harness, ascender / croll, auto descender, footloop, jammer, carabiner, long cowstail, and short cowstail.
An adventure to the deep part of the earth was soon started by leaving the basecamp to get to the edge of the cave as the track. There were some tracks in Jomblang cave with various heights, from 40 up to 80 meters. Since this was the very first time for us to do vertical caving, the shortest track, known as the VIP one, was chosen. The first 15 meter from the VIP terrace was a slope that was possibly stepped, and we continued to go down on a 20 meter rope to get to the bottom of the cave. The feeling of scared and nervous when we hung in the air was suddenly disappear when we stepped our feet on the ground.
Surprisingly, the view in front of us was awesome. When we were above, we could only see barren region with hardwood and when we were hanging on the rope to get to the bottom, we could only see karst, but in the bowl of Jomblang cave we could really see the green view of fertile and dense vegetation. Various kinds of moss, fern, bush, and big trees densely grew. A forest with different vegetation from the land above it was usually called ancient forest. Since the geological process of the land happening in the past, those vegetations were continuously growing up to now.
Luweng Grubug, a Visible Heavenly Light
The cave adventure we did was not only stopped at Jomblang. We still continued our journey to Luweng Grubug by entering an entrance, which was an extra large edge of a cave. Jomblang and Grubug were connected by an alley with 300 meters length. Many beautiful ornaments decorated this alley, such as crystal, stalactite, and stalagmite. Walking for a while, we heard thundering sound from the river stream and saw light in the dark. We curiously fastened our steps to see what was going on.
Wonderful scenery, which was really fascinating, spread in front of us. An underground river which still had the same system as Kalisuci flew quickly. The sun light that got in through Laweng Grubug formed a 90 meter light pillar and shone the flowstone in the dark cave. The water drops also made it become a more perfect view.