Material World: Clenched buttocks and sulphurous gas at Mount Etna

Updated Tuesday 18th November 2008

John Murray has been monitoring Mount Etna since 1975 - a tale of Clenched Buttocks and sulphurous gas

It had been one of those research trips where everything was going wrong. We were four weeks into a five week field trip to Mount Etna and we had not finished the levelling, dry tilt or GPS measurements. We'd lost precious time with three weeks of ice and early snowfalls that made work at the summit impossible, and our trusty, 17-year old digital level had let us down. The manufacturer had been good enough to send us a replacement, but that took a stressful five days, and to cap it all Etna had decided she would send a lava flow to destroy one of our treasured stations that I had installed 21 years ago.

The last thing I wanted to do was spend a day being nice and polite to the BBC.

Studying Mount Etna Copyrighted image Icon Copyright: John Murray Studying Mount Etna

On the day of the BBC's arrival the weather was perfect. Their plane was to land in the afternoon, but with things as they were we couldn't waste the opportunity, so at first light we set off for the summit of Etna.

Andy Bell, a seismologist from Edinburgh, was leaving us the following morning, so it was our last day with five people, and thus our last chance to measure the critical stations in the Valle del Bove.

This was a borderline-dangerous escapade down into a vast cauldron five kilometres wide and one kilometre deep, that, for the previous five months, had been filling up with flow after flow of loose Aa lava: red-hot piles of loose unstable stones sharp as glass.

On a good day this would have taken a solid eight hours of hard slog, but this was not a good day.

The new lava had made the task almost impossible, so after ten hours we were still floundering around in pitch darkness, out of radio and mobile phone contact, with the streams of lava glowing behind us in the darkness.

When at last we limped bruised and bleeding over the lip of the valley, Material World producer Martin Redfern's voice over the phone was a paradigm of polite restraint. "Delighted to make contact…" etc, etc.

An interview on Mount Etna Copyrighted image Icon Copyright: John Murray The Material World team get an interview

Not only had we not been there to meet them, and uncontactable to boot, but it transpired that I had given them the wrong website for their Bed-&-Breakfast, so instead of being round the corner from us in Nicolosi, the highest village on the volcano, they were 20 miles away in Adrano, at the foot of the mountain. Oh dear, oh dear, oh dear, and a lot of swearing…

The following morning was a different kettle of fish. We were scarcely half an hour late when we finally met Martin and presenter Quentin Cooper at the Sapienza halfway up the south side, from where we began the slow ascent up the vehicle track to the top, with six of us crammed into our 4x4, together with seven GPS kits, tripods and rucksacks.

The nature of the work, and the difficult and sometimes dangerous conditions, means that at least 4 people (2 teams of 2) are required. This year there is Saskia van Manen, a Dutch PhD student at the Open University, Melanie Zacheis, completing her Masters at Portsmouth University, and Kate Gladstein from Vermont University, U.S.A., whose work here on Etna will form part of an undergraduate project.

Etna does not always erupt its lava from the summit craters. Now and again a new fissure opens in the side of the mountain, and this had happened in May, and the lava was still sluggishly oozing out. Before the main business of the day, we took an hour's scramble to look at how the eruption was progressing.

It's wise to keep a gas mask to hand Copyrighted image Icon Copyright: John Murray It's good to keep a gas mask to hand

We were able to stand on the edge of the erupting fissure, with acrid sulphur dioxide and hydrogen sulphide pouring from the abyss, but there was total silence, and no sign of flowing lava. Only when the mist cleared could we see the bluish gas and the deep red of the active flows far below us in the Valle del Bove. Between us and the flows the lava was travelling through a series of underground channels.

Our work concentrates on measuring with extremely precise instruments how the volcano changes shape from year to year, as the magma forces its way from deep within the volcano to the surface, and as portions of the volcano slide downhill or jostle in response to shifting gravitational or tectonic forces. I have been doing this once to three times a year since 1975, and this year we have already found some exciting results.

Not only has much of the land on this eastern side shifted more than one metre towards the sea, but there has also clearly been an injection of magma down the north side of the volcano, deep beneath the surface.

We measure vertical movements and ground tilt of more than 300 stations over the summit and flanks of this huge volcano with a precise level - now old and venerable technology, but still twenty times more accurate than any other method of height measurement.

However with six of us in the vehicle we have had to leave this equipment behind. Today we would be using dual-frequency GPS, capable of measuring our 100 stations to an accuracy of a few millimetres over distances of tens of km. Up to seven GPS kits are set up at stations all over the mountain at the same time, and left running for between 20 minutes and ten hours.

As the recording got under way, it became clear that this is to be at least partly a fly-on-the-wall affair, with the odd more structured interview.

We approached the first GPS station, the microphone was switched on, but as the girls began to set up the equipment a thought crossed my mind, and I nipped across to obstruct the view of the handset, but too late.

Quentin opened with "I can't help noticing that the name of this station is 'Clenched Buttock'…". Oh dear, oh dear, hope they cut that bit out.

Students have been naming these stations now for nearly 40 years, and they range from the poetic to the nostalgic to the comic to the downright rude, but they were all topical at the time and all have a story to tell, and bring back more than anything the flavour of trips long past: Crack of Doom, Eleanore's dream, Cat's Paw, Desolation, Lightning Ridge, Big Girl's Blouse, Defenestration, Sellotaped Egg, Monkey Boy, Chocky's Hill, and the greatly-regretted Rosanna, now buried deep beneath the accumulating lavas of the 2008 eruption.

We quickly got used to the microphone, even forgot it was there. All in all things seemed to go well, though I was aware of making the occasional gaff. There were countless interviews with me and each of the women, but I still felt we were only scratching the surface, and that only a small part of our work, and of the multi-faceted nature of Mt Etna and its eruptions, was being recorded.

At the end of the day we made the ascent to the edge of two of the four summit craters.

An otherworldly vista on Etna Copyrighted image Icon Copyright: John Murray An otherworldly vista

Normally one can hear explosions or at least puffs of gas deep down inside, but there was still total silence, so Radio 4 listeners will have to be content with descriptions of the yellow sulphurous deposits and our coughing fits as the wind takes the gas in our direction now and again.

The BBC's visit marked a turning point in the trip. After they had gone, the weather changed to its normal calm, sunny, autumnal best, and in the final few days we managed to get everything completed.

Take it further

The Material World from BBC Radio 4 and The Open University

The BBC's Martin Redfern reported on this trip for From Our Own Correspondent
Listen to Martin's report

Discover the science behind volcanic eruptions

How was the entire continent affected by the 1783 Laki eruption on Iceland?

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