Nyabikuri-Rudi (Ubuvumo)

Michael Laumanns - 29/11/2015

(North province, Virunga mountains, Burera district) Co-ordinates: S01°25,914’; E 029°39,685°. Alt. ca. 2,212 m. Explored by the 2003 Swiss-German speleological project. The cave has two entrances (Nyabikuri and Ruri entrance doline) and two daylight holes in the roof of the (northern) Nyabikuri section. The lava tube with the lava stream coming from the 3,474 m high Muhabura volcano is nearly non-branched and spacious with a diameter of up to 15 m. In the northern section some neo-tectonic cracks intersect the whole lava tube. The cave is quite humid. A small water stream uses the main gallery in periods of wet weather. Some water accumulates about 590 m from the N entrance in a nasty and deep puddle of mud. Around the daylights one can find a significant number of human skeletons (about 30 individuals), which shows that the cave was used as a hideout during the genocide of 1994 or even before. 2,145 m from the north (Nyabikuri) entrance another small collapse doline is reached (at E 029°40,125°; S 01°26,764’, alt. 2,041 m). From here the lava tube continues in a 1,209 m long southern section, called Ruri. Finally, the cave gets completely plugged with sediment. A human skeleton was found near to the plugged southern end of the cave. With the exception of the most southerly part of Nyabikuri-Ruri the floor of the lava tube is mainly made of original lava (including ropy lava and red lava) and partly covered by breakdown. Lava stalactites are rare. Some small bat colonies inhabit the cave. Furthermore, spiders, beetles, moths, snail shells and caterpillars were observed. Survey and description according to Laumanns et al. (2004, 2007).