Photo: Doug Perrine Photo: Doug Perrine Photo: Doug Perrine

Over time, our idea of what constitutes the extreme edge of diving tends to change. Once, a dive beyond 100m was considered insane. Now free-divers routinely pass that mark, and technical divers have been three times that deep.

There is, however, one diving niche which has been found to be even more dangerous than initially presumed, and which currently has fewer practitioners than 20 years ago. The Edge of Creation is a site that can be found on the southeast coast of Hawaii Island. Here, hot magma from the bowels of the earth enters the Pacific Ocean, creating new land in a flurry of explosions that occur when molten rock at 1,100ºC meets sea water.

To get an idea of what being underwater near these eruptions is like, try watching the film Saving Private Ryan with surround sound at full volume. If you feel the explosions in your chest and go deaf at the same time as Tom Hanks' character, it's loud enough.

When you are standing on the shore, watching lava enter the ocean and dodging the lava bombs that are blasted into the air, going for a scuba dive in this devil's cauldron might not be the first idea that would enter your mind. Dr James Moore, however, wanted to be the first person to actually see the formation of pillow lava, which is created when lava cools underwater. Moore, a geologist assigned to the Hawaiian Volcano Observatory, had his chance in 1971 when lava from Kilauea Volcano entered the ocean for a brief period. Moore recruited underwater cinematographer Lee Tepley to film the phenomenon. Tepley made some five dives on lava entries in 1972 and 1973, and produced a film, Fire Under the Sea. His footage is still shown at the visitor centre at Hawaii Volcanoes National Park. For several years there were few lava flows in the area, but when it started again, a new generation of film-makers was ready.

In 1986 Dick Bradley was the first to shoot video of an underwater eruption and have it broadcast on US national news that evening. 'Every dive was completely different,' says Bradley. 'One dive can be completely mellow, then two or three hours later it can be really explosive. You'd be down there filming on the slope, and all of a sudden it would explode under your stomach, and it would be like somebody sticking a fist in your stomach. The shock waves go right through you. You're trying to steady yourself for a shot, and pay attention to the explosions and implosions… and you don't even notice your hands are getting cut to ribbons by the sharp volcanic glass.'

Even more dangerous than the steam explosions and lacerations, are the frequent avalanches, when gravity overcomes the unstable pile of fresh volcanic debris. 'Visibility would go to zero,' says Bradley. 'It would spin you right around and you'd be going backwards. You wouldn't know which way was up. Your bubbles would be going sideways. Material is falling around you and you can't see anything. Our worst experience was getting caught in a current that was taking us right into the path of the material that was going into the ocean. The boat picked us up just as the water was getting so hot that we couldn't stand it.'

Lee Tepley and James Watt were underwater in December 1986 when a major shelf collapse occurred. 'I remember two explosions,' says Watt. 'All of a sudden I saw Lee get buried in rock and carried away.The boat driver said that a 200 by 60-foot [60m by 18m] section split off all at once. It was a giant slide. As hard as I kicked, I was still going down. I pulled out at about 180 feet [54m] and Lee took the plunge to about 300 feet [90m]. I thought he was dead.'

Tepley eventually surfaced, bleeding from gashes on his arm and leg. He and Watt grabbed spare tanks and did an open-ocean drift recompression. After that, both gave up lava diving, as did other adventurers who had similar near-death experiences.

About this time, Bud Turpin, a Hawaii contractor, diver, and fisherman, made his first dives on the lava flow. 'When we started diving it, there were a lot of fish around, so I brought my speargun and started spearing fish,' says Turpin. [DIVE: 'You were diving the lava flow just because it was a good place to spear fish?']. 'Yeah, we noticed there were big ulua [giant trevally] around it, so we started diving it two or three times a week to get the ulua.'

Turpin found that he could stick his knife into the semi-liquid lava and pull it around. Later he substituted a gaff and was able to control the lava enough to form it into shapes. With practice, he was able to create rough sculptures of animals and other forms. His artistic creations are ephemeral and cannot be removed from the ocean. He is the only artist in the world working underwater in the medium of molten lava. The latest evolution of his technique occurred in 2005 when he discovered that, using welder's gloves, he could grab the lava with his hands and shape it.

Turpin says he has made more than 200 dives on the lava flow. Recently his son, Shane Turpin, has been documenting his adventures on video (www.thelavaman.com). Bud Turpin has seen some amazing sights, such as a nearly metre-wide 'fire hose' of red lava shooting out of a cliff, after a shelf collapse broke off the lava tube like a severed artery. 'I would say it is among the most extreme diving that can be done,' he says. 'The conditions are extremely dangerous… from zero visibility, to landslides that can drag you down to fatal depths - not to mention the hot, scalding water and lava.'

The only dive operation to offer lava dives to the public terminated the programme after 18 hectares (44 acres) of solidified lava collapsed into the ocean on 28 November 2005. The company realised that any diver anywhere near the area at the time of that collapse would never have been seen again. Two weeks later, however, Turpin was diving there again. He saw firefalls of red lava and experienced numerous small avalanches. 'I think I saw God,' he remarked, upon exiting the water.

Turpin picks his diving days and spots carefully, sometimes avoiding the flow for months when conditions are bad, but expects to keep diving it 'as long as it continues to go into the ocean.' Asked if he's crazy, he answers, 'I've been called that… Sometimes I think I might be, too.'

For more information about Hawaii's underwater explosions, see the website http://hvo.wr.usgs.gov/hazards/oceanentry/deltaexplosions/