Tuesday, February 23, 2016

[Geology2] What it's like to drop into the crater of a live volcano (Part 2)

What it's like to drop into the crater of a live volcano

Mark Robinson

Tuesday, February 23, 2016

Dropping into the crater of a live volcano isn't the same as rappelling off the edge of the Niagara Escarpment in Ontario. There's a lot more gas and falling rocks in a volcano. And a lot more molten rock at the bottom.

Note: The following is Part II of Mark Robinson's first-hand experience of travelling to and dropping in the world's most-dangerous volcano | Read Part I here: Nothing prepares you for the fear of it all

Despite that, I'd made it to the halfway point without too much incident. A few falling rocks and some steam vents, but no screaming or wetting myself. But the next part was going to really test me. George Kourounis had gone down the first pitch (that's what we mountain climbers call the part you climb down along a rope. Two pitches would be two separate sections of rope) with me, but now I had to take the second pitch on my own.

And it was a lot steeper than the first. In fact, it was a sheer cliff with just a bit of an overhang after the first two feet of rock. That meant that I might be airborne for a little bit.

I leaned back into my harness and let the rope glide slowly through my brake and in moments I was pushing away from the rock face and dropping foot by foot down the cliff face.

That was the point at which I forgot completely which way you had to guide the rope to slow down. I yanked the rope to the right as I began to drop faster than I was comfortable with. Unfortunately, that was the exact wrong thing to do as slowing down is accomplished by tucking the main rope under your backside, to the left. I dropped eye-wateringly quickly and in my moment of panic, I somehow caught my shirt on the brake and tore a hole in it. My good StormHunters shirt now has a lasting testament to my "Ooops" moment on the side of the volcano.

Much to my relief, I was able to get things under control and slid to halt about 30 feet below the edge of the cliff. I breathed in and out for a bit and then fumbled my way back into motion, taking a bit more care to slowly drop the rest of the way down to the bottom of the pitch.

On another world entirely

That was when I stopped and realized that I was on another world entirely. I've often imagined what it would be like to walk on the surface of Mars, to see the sand and rock of another planet.  I now know what those first astronauts are going to see. I unclipped from the ropes and gazed over a vast ash plain. Everywhere I looked, rocks were scattered about, having fallen from the crater walls high above. Huge boulders were driven partway into the reddish brown of the dust that lay everywhere. Huge fissures rippled across the plain, steam and gases rising in writhing columns into the air. Frozen ropes of cold lava oozed through the dirt, looking like sea monsters trying to dive below a ruddy surface.

But the overarching feature was the vast column of volcanic gas that lifted from the massive open crater in front of me high into the clouds far above. The cloud wasn't quite the right colour to match those I was used to seeing in Tornado Alley. It had a blue tint to it, much more like what you'd see from a campfire. In that cloud was a trio of deadly gases; sulphur dioxide, hydrogen sulphide, and carbon dioxide.  The first two are deadly to humans if inhaled in a high enough concentration, but the third, CO2, is critical to life on earth.   

Carbon dioxide is a major component of the greenhouse gases that help keep our planet warm enough to sustain life. Volcanoes are a major natural source for the gas and at one point in our planet's history, they helped unfreeze an ice age that was so extensive almost the entire surface was covered in ice. Without the CO2 pumped out by volcanoes, we might still be trapped as an icy ball instead of the tropical planet we now inhabit. 

The biggest lava lake on Earth

I walked towards Brad and Chris as they worked on the final rope drop to the edge of the lava lake that despite how far I'd come, still looked far away. The final drop was still at least 150 m down. As I stood at the edge of that final drop, my heart sank. This was going to be a far more difficult drop than the others. Perhaps beyond my abilities.  A massive overhang with a huge amount of airborne rope beckoned and that mean that I might not be able to make that final stage.

But I could now see the lava lake itself much closer up and it was like nothing I'd ever seen in my life. Bright red lava jetted upwards through cracks in the dark crust that heaved and moved across the surface of the lake. Huge jets of gas blasted upwards as spatters of molten rock shot skyward. Every few minutes, a new gout of red lava ripped a hole in the black crust and roared into life.  Even from as far away as I was, the heat hit me like a wall.

At 1,200oC, molten rock is a spectacular thing to witness and the lava lake at Nyragongo is the largest in the world. At over 200 m across, it holds a vast amount of liquid rock that boils much like a pot on a stove. And like that pot, huge amounts of gas escape as bubbles that work their way to the surface and rocket skyward.

What I was watching was the final stage in a vast journey of rock that started deep within the mantle of our planet. Heated by the tremendous pressure and radioactivity deep within the core of the planet, molten rock oozes up through cracks in the crust and finally emerges as lava at just a few select places.

I'd made it as far as I could and the lava lake below me was one of the most incredible sights I've ever seen. And given that Nyiragongo is just one of at least six lava lakes on the planet, my journey is only just beginning.

Next time, I'll make it all the way down.

See the video here:




Posted by: Lin Kerns <linkerns@gmail.com>


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