UIS Commission on Karst Hydrogeology and Speleogenesis

In the period August 5 ? September 15, 2007 the Ukrainian Speleological Association (Ukr.S.A.) have conducted the regular expedition of the "Call of the Abyss" Project to Krubera (Voronja) Cave in Arabika Massif, Abkhazia, the deepest cave in the World. A scientific program of the expedition and cave surveying has been supervised by the Ukrainian Institute of Speleology and Karstology (UISK).

The expedition, led by Yury Kasjan, consisted of 41 members including 29 cavers from Ukraine (Kiev ? 9; Simferopol ? 6; Poltava ? 5; Kharkiv ? 4; Sevastopol ? 2; Ivan-Frankivsk ? 1; Khmelnitsky ? 1; Kamenetz-Podilsky ? 1), 10 cavers from Russia (Moscow ? 5; Ufa ? 2; Kazan ? 2; Novokuznetsk ? 1), 1 caver from Belorussia and 1 caver from Great Britain. Some other cavers from Dnepropetrovsk (Ukraine) and Moldova, which have been working in the area as separate groups, also helped in Krubera operations.

There were three main exploration fronts pursued during the expedition:

1)  The bottom sifon "Two Captains", explored by the previous Ukr.S.A. expedition in August 2006 to a squeeze at -14 m (-2158 m of total depth). In this expedition divers Gennadiy Samokhin and Yury Evdokimov made several dives pushing the sifon further on. The farthest (140 m) and deepest (-45.5 m) point has been reached by G.Samokhin, which gave a new depth for the cave at -2191 m. The sifon continues down as a steeply inclined passage.   

2) The Nekujbyshevskaya branch, a distinct branch diverging from the main one at -250 m and stretching to the north-west, the direction opposite to the overall trend of the main branch. Following the major breakthrough made by the previous Ukr.S.A. expedition, the team led by Kyrylo Markovskoy explored many new passages and pits there to the depth of -1293 i.

3) Side passages and sifons at various depths in the main branch between the bottom and -1775 m. G.Samokhin and Y.Evdokimov made 75 exploration dives in various sifons (not counting free dives in sifons on the main trail during regular transport operations). The main results were achieved in a side branch previously ended at -1775 m by the "Blue Lake" sifon. Behind the "Blue Lake", a series of air-filled passages has been explored, separated by 6 sifons. The farthest sifon "Yantarny" has been explored for 130 m in length and 19.5 m in depth and continues. The deepest point in this branch has been reached at -1841 m. 

Altogether, 2510.5 m of new passages has been surveyed during this expedition.

The updated 3D model of Krubera Cave (VRML) can be viewed at

New total figures for Krubera Cave:
- Total depth:  2191i
- Total length: 13 232i

The scientific program performed during the expedition included temperature measurements, geological observations, microbiological sampling and sampling of clastic sediments (for mineralogical analyses) and speleothems (for dating and isotope analyses).

During 29 days of underground operations in this expedition five underground camps were in use. The expedition has removed all camp wastes to the surface and further from the mountains, including those from the deepest camps (including camps at -1960m and -1640m). 

Yury Kasjan and Alexander Klimchouk, the CA Project co-ordinators