[1] The difference in elevation of the highest cave entrance (Arbaika) and its deepest explored point is 2,199 ± 20 metres (7,215 ± 66 ft).

Ukrainian diver Gennadiy Samokhin extended the cave by diving in the terminal sump to 46 metres' depth in 2007 and then to 52 m in 2012, setting successive world records of 2,191 m and 2,197 m, respectively.

To the northwest, north, northeast, and east, Arabika is bordered by the deeply incised canyons of Sandripsh, Kutushara, Gega and Bzyb rivers.

A plateau-like middle-altitude outlier of the massif in its south sector is Mamzdyshkha, with part of the plateau slightly emerging above the tree line.

Among several hundred caves known in the Arabika Massif, fifteen have been explored deeper than 400 m and five deeper than 1,000 m.[citation needed] Krubera Cave is located at 2,256 m above sea level in the Ortobalagan Valley, a perfectly shaped, relatively shallow, glacial trough of the sub-Caucasian stretch, which holds the advanced position in the Arabika's central sector relative to the seashore.

The Porphyritic series forms the non-karstic basement of Arabika, which is exposed only on the northern and eastern outskirts, locally in the bottoms of the Kutushara and Gega River valleys.

The Upper Jurassic succession begins with thin-bedded Kimmeridgian–Oxfordian cherty limestones, marls, sandstones and clays, which are identified in the lower part of Krubera Cave.

[6] Major faults of the sub-Caucasian orientation delineate several large elongated blocks that experienced uplift with different rates during Pliocene and Pleistocene.

[8] Recently an outstanding feature of the sea floor topography near Arabika has been revealed[11] from a digital bathymetric map that combines depth soundings and high-resolution marine gravity data.

This is a huge submarine depression in front of the Zhovekvara River mouth, which has dimensions of about 5 x 9 km and a maximum depth of about 380 m (1,250 ft).

Tracers injected in the Kujbyshevskaja Cave and the Iljukhina System were detected in the Kholodnaja Rechka and Reprua springs, proving groundwater flow to the south-southwest across major tectonic structures over a distance of 13–16 km as the crow flies (Figure 1).

The tracer from Kujbyshevskaja Cave was also detected in a borehole located between these two springs, which yields groundwater from a depth of 200 m (660 ft) below sea level.

The results of the dye-tracing tests demonstrated that groundwater flow is not subordinate to the fold structure but is largely controlled by faults that cut across the strike of major folds, and that the large part of the central sector of Arabika is hydraulically connected to the springs along the seashore and with submarine discharge points.

It is difficult to interpret these facts in terms of the development of karst systems controlled by contemporary sea level, or within the range of its Pleistocene fluctuations (up to −150 m).

In combination with the existence of the Arabika Submarine Depression, all these facts point to the possibility that karst systems in Arabika could have originated in response to the Messinian salinity crisis (5.96–5.33 Ma)[11] when the Black Sea (Eastern Paratethys) could have almost dried up, as did the adjacent Mediterranean, where the dramatic sea level drop of ~1,500 m is well established.

The biocenosis of Krubera-Voronja is composed of more than 12 species of arthropods of several groups, such as pseudoscorpions, spiders, opiliones, crustaceans, springtails, beetles and dipterans.

[12] Krubera-Voronja cave is inhabited by endemic species, including four springtails discovered during the CAVEX Team expedition of 2010: Anurida stereoodorata, Deuteraphorura kruberaensis, Schaefferia profundissima, and Plutomurus ortobalaganensis; the last of these is the deepest terrestrial animal ever found on Earth, living 1,980 metres (6,500 ft) below the cave entrance.

The subterranean amphipod crustacean Kruberia abchasica caught by Gennady Samokhin in August 2013, during dives in the siphon 'Dva Kapitana', dwells at the deepest part of the Krubera Cave (at the depth of −2,175 metres).

[14] At the beginning of the 20th century, Arabika was visited by French speleologist Édouard-Alfred Martel, who published several works about the massif.

In the early 1960s, Georgian geographers led by Levan Maruashvili began exploring caves in the high sector of the massif.

From 1982 onwards, the Kiev cavers started systematically working in Krubera Cave, located less than 200 meters from the Kuybyshevskaya entrance, hoping to connect with the Arabikskaya System and increase its total depth by 60 m. Exploration progressed slowly because critically tight meanders between the pits required enormous amounts of work to widen them to a passable size.

have been undertaken within the frame of the multi-year project named "The Call of the Abyss", coordinated by A. Klimchouk, Y. Kasyan, G. Samokhin and K. Markovskoy.

Besides the Ukrainian speleologists, cavers from many countries such as France, Spain, Russia, Moldova, Bulgaria, United Kingdom, Ireland, Israel and Lithuania have taken part in different expeditions of the Ukr.S.A.