Lava lovers

Lanzarote is no ordinary island. Thrown up from beneath the sea in a series of cataclysmic volcanic eruptions, this island, like the others in the Canaries, is testimony to the fantastic power of the natural world. Today the cones and craters are dormant, but everything about the landscape gives a clear indication of the dramatic events of the past. The views from the air are both spectacular and intriguing, and if you visit the Timanfaya National Park, which is an absolute must, you will be awestruck by the scenery. Black, molten lava lies twisted and contorted, as though it were icing extruded on to the face of some giant Christmas cake. Sulphur wafts in the air and the rocks are so hot that you could grill food on them. There is no vegetation for miles; it kindles a vision of Mordor in Lord of The Rings, with its tragic history of communities consumed by lava, ash and darkness. However, these are merely the surface features – even more fascinating, especially for divers, are the subterranean cavities and lava tubes.

Lava tubes are only formed in areas of volcanic activity and derive their origin from flows of molten lava. In their original state the tubes were formed above water – in an air-filled environment. Where these sites are found below sea level, it is due solely to the rising of ocean levels since the last glacial period. These tubes are formed in basalt rock, which varies in colour between grey and black. As a result, the environment is ominously dark and seems to absorb more light than most other natural caves. Apart from the general gloom, these sites are frequently characterised by sharp rocks, stalactite or icicle-like roof projections and, as with any overhead environment, many contain quantities of fine silt. The small bay at Playa Chica, near the harbour town of Puerto del Carmen, for example, slopes gently to an abrupt drop off at around 20m. The wall itself is only 10m or so in height and below the bottom descends into the ever-deepening grey gloom of the Atlantic. Secluded beneath the overhanging wall, there are dark openings to places such as Altar Cave and the Cathedral. The first is a small recess, but the latter presents an altogether more awesome void. This is a cavernous entrance giving a very good idea of the spectacular nature of the tubes. The tunnel is less than 30m in length, but at its mouth it is 20m wide and more than 10m high.

Ascending from 30m back towards the shallow, sheltered water of Playa Chica, divers can make another subterranean foray into a short tunnel beneath the harbour wall. Both of the black, rocky walls which envelope Playa Chica are, in fact, natural features – ancient lava flows – and unknown to visitors the southerly limb is partially hollow. This may not be as spectacular in size as the Cathedral, but once again it’s an interesting deviation. The tunnel is several metres wide and large enough to negotiate with conventional equipment. Although the tunnel is festooned with boulders, daylight is visible at all points. The passageway is so shallow that at low water, small air pockets are formed, but at high tide the entire passage is water filled and scores of small golden cardinalfish, which are common in all the caverns of the Mediterranean area, flit to and fro.

There are more swim-throughs and volcanically formed caverns at Mala, another popular dive site located in the northeast of Lanzarote. Here, more distant from the large tourist centres such as Playa del Carmen, the visibility is in excess of 30m, marine life is profuse and, with depths well within the recreational sphere, everything feels to be that much more colourful.

However, the most fascinating site of all is the tube which finally dives beneath the sea at Jameos del Agua on the northeast coast of Lanzarote. Amazing, intriguing, perhaps downright incredible, are all terms that can be applied to this renowned site. Jameos del Agua is, along with the Timanfaya National Park, one of the principal tourist attractions on the island. Many hundreds, if not thousands, of people visit the site daily and, diver or not, all will marvel at the spectacular tube. In one momentous event some 5,000 years ago, a giant river of red-hot lava drained to the sea, leaving a huge void in its wake – a tunnel big enough to accommodate both a café and an auditorium capable of seating some 600 visitors. For much of its length, the tube lies only a few metres below ground, yet on the surface there is little or no indication of its existence. From its source at Mount Coronas to its terminus way out to sea, some 7km of tunnel have been charted to date. The upper 5km is dusty and bone dry, but the final section, which lies below sea level, is filled with some of the clearest water imaginable. This flooded tunnel of seemingly static water is an amazing sight to behold. In places, the walls appear as smooth as glass, moulded, sculpted and shaped like a sub-aquatic version of a Cresta Run. Running in roughly a straight line from the dormant volcano to the sea, this is perhaps the finest lava tube in the world. Access is gained at a few points, such as Jameos del Agua where the roof has collapsed.

Today, sadly, no diving is permitted at Jameos del Agua which has been assigned special protection due to the presence of blind white crustaceans. Such species are normally encountered in the deep ocean, so quite why these cave-dwellers (Munidopsis polymorpha) do so well in the tube is not fully understood. The crabs are thought to be unique to this site and are conspicuous, plentiful and thriving in the open-water lake. One can only wistfully imagine what it must be like to explore this fantastic tunnel. In the mid-1980s Jameos del Agua was the site of the longest submarine dive in the world, when the leading Swiss diver Olivier Isler reached a blockage in the cave after a 1.6km underwater penetration. Heavily equipped with a huge array of 20-litre open-circuit cylinders and two large scooters, this was a momentous dive and a massive achievement. Whether this is the absolute terminus of the lava tube remains to be seen. To date, Isler is the only explorer to have reached the ‘end’ – 1,620m in length and 64m in depth – but it is hoped that a more thorough study of the site will be conducted in the near future. That the blockage might prove to be localised, passable and eventually lead to the open sea, is an exciting concept.

We were able to make a series of dives in an exquisite part of the tube named Seven Lakes, a stretch of flooded passage with visibility well in excess of 40m. Interestingly there were no blind crabs at all in this sector of the tube, despite its evident proximity to Jameos del Agua. The tunnel terminates at an abrupt wall of boulders, a massive natural roof fall, directly beneath the main collapse entrance of Jameos del Agua. A distinct, though slight, tidal flow was observed on these dives and the water level varied accordingly.

Disappointingly, even with the most streamlined sidemount equipment, there is no possibility of an underwater connection with the main continuation of the tube which continues out to sea from the easterly side of Jameos del Agua.

That other unexplored lava tubes and, perhaps, presently unknown life forms are to be found hereabouts is an exciting prospect. For anyone interested in looking a little further than sun, sea and alcohol, Lanzarote is a fascinating place.

NEED TO KNOW
It’s a four-and-a-half-hour flight from the UK to Lanzarote, which is in the same time zone as the UK. In December, air temperature is around 20ºC, while that all-important water temperature is a balmy 18ºC, and it’s the same underground. Note: cave diving should not be attempted without having undertaken proper training.