Volcanoes, as you might imagine, are often quite dangerous places. In some instances, volcanologists like to stand as close to a bubbling lake of lava as possible in the name of science. Seduced by the primeval hazard, photographers, filmmakers and daredevils often like to join in on the adventure.
Whether you're a bonafide scientist or not, you are equally likely to be murdered by a rogue bit of volcanic debris, particularly if it's a so-called lava bomb. As the following videos clearly show, volcanic paroxysms are fairly unpredictable, and the fireworks they unleash can often get quite close to the adrenaline junkies nearby.
Forget the grisly fate that awaits particularly clumsy or fantastically unfortunate volcano visitors, though - the physics of the volcanic debris itself is surprisingly fascinating.
A close call for the “dangerman” Geoff Mackley atop Mount Etna a few years back. (via YouTube)
Think of glass blowers, those versatile magicians of the translucent world that craft complex sculptures out of molten sand and metallic wands. Glass can be formed into fish, birds, spheres, spears, fountains, flamingoes and fossils. Lava, when it cools extremely quickly below a temperature known as the glass transition point, becomes similarly serpentine and malleable.
If the lava is extremely fine, it can be lifted up into the air by an explosion and then continue to rise into the sky. Hot, air-filled lava blebs are considerably less dense than their surroundings, and they will continue to move upwards - perhaps a sort of a gigantic column of volcanic ash, so long as they are lighter - or less dense technically speaking - than the air around them.
Somewhat larger blebs will fly out of the volcano and become stretched as they do. When they form elongated, apostrophe-like shapes and cool that way, they are known as Pelé's tears, named after the Hawaiian fire goddess. Longer, thinner strands of this volcanic glass are referred to as Pelé's hair.
Add a few more clumps of rapidly cooling lava together, mix in a decent amount of gas, and you get pumice - yes, that stuff you exfoliate with. Pumice is essentially an aerated clump of volcanic glass, and it's density is so low that it will float in bodies of water.
If a lava bleb is ejected as a fairly sizeable, unwieldily mass, it takes too long to cool and turns into a solidified stone, not glass. These chunks are appropriately known as volcanic bombs (or blocks if they're particularly massive).
The surfaces of volcanic bombs can get a breadcrust-like texture as they cool and crack. In fact, this characteristic feature is what makes them stand out from the crowd of surrounding rock types.
They're not molten on the outside, but they are still hundreds of degrees hot. Whether they are can flying out of a lava lake, down from a collapsing fire fountain, or out from volcanic explosion at supersonic speeds - if they hit you, they'll crush you and cauterise your skin in a handful of seconds. If they fly directly towards you, they can tear through your abdomen like superheated bullets.
So with all this danger involved, why the hell would volcanologists want to try and catch them? Well, unlike lava that's spent ages cooling, these glassy shards contain the freshest records of the chemistry of the source volcano's magma.
As soon as magma becomes lava by erupting at the surface, its chemical and physical features begin to change and alter beyond recognition. As fresh lava bombs or blebs have just emerged from beneath the surface, they are often the least altered sample that researchers can get their hands on. So sometimes you've just got to take a risk and try and catch one.
You could always go up to the rim of a lava lake and grab a fresh sample form the inferno's ring, but that's a different story of danger for another time.
