Lava Tube Caves
Two readily accessible and fascinating caving areas in Kenya are recommended for special consideration. They comprise of lava tube systems, formed in a period of recent volcanic activity, and are totally different from limestone caves. Relatively rare, they are believed to have been formed when molten lava, of the correct type and viscosity (pahoehoe lava), flowed down a slope of an ideal angle. The outer layers cool and solidify, but the core continues to flow, and in some cases, evacuates itself completely to leave behind an empty tube. Numerous unusual features can be found and include lava ropes, benches, lava stalactites and stalagmites and a variety of secondary formations. The latter are produced by the deposition of minerals dissolved in the ground waters. The secondary formations are exceptionally fine in cave 35A on Suswa where very unusual and beautiful stalactites and stalagmites are found. Many of these formations are quite fragile and great care must be taken not to touch them. Primary lava tube formations are a record of the past and any damage done to them will never heal.
Suswa is a magnificent example of an extinct volcano in the Rift Valley. Many caves are found on its E slopes. None of them are long or complex and no special equipment or knowledge are required to tackle the systems. Leviathan is located in the Chyulu Hills and is at present the world’s second longest lava tube system. The total length of its passages add up to over 11 km. The complete traverse is possible in one long day. This would be quite demanding as long sections of the tube involve balancing over slippery boulders. There are also a few short squeezes. Near the top of Leviathan a short length of rope would be useful to help negotiate traverses on the poor and steep rock in this section.
Numerous animals inhabit the caves and some others have fallen into them. There are several skeletons of large animals in Leviathan; none of these should be touched. Several different varieties of bats inhabit the caves. Their guano can be unpleasant and slippery to walk through. The bats themselves pose no real hazard; as they are not carnivorous they are not rabid.
The entrances to the caves are invariably formed by Collapse Holes where the roof of the tube has fallen in. The vegetation around these holes is dense and often includes a characteristic palm-like tree (Dracaena), or fig tree. On Suswa collapse holes are best located by orienteering techniques (10 m = about 12 paces). Caving grades have a C prefix.