FYFD

Tag: eruption

  • Deciphering Krakatau

    Deciphering Krakatau

    In 1883, the eruption of Krakatau (also called Krakatoa) shook the world, sending shock waves and tsunamis ricocheting across the globe. Some of the smaller waves hit shorelines in the Atlantic and Pacific that were entire continents and ocean basins away from the original explosion. At the time, scientists were so perplexed by the phenomenon that they blamed coincidental earthquakes for the wave action.

    Only when Tonga experienced a similarly devastating volcanic eruption earlier this year were scientists able to verify what they’d long suspected: these smaller tsunamis were not caused by solid material displacing water; instead they are the result of atmospheric pressure waves coupling to the ocean. Follow the full story over at Quanta. (Image credit: M. Barlow; via Quanta; submitted by Kam-Yung Soh)

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    Fagradalsfjall Volcano

    We’ve seen a lot of drone photography from volcanic eruptions in the last few years, but this footage from Iceland Aerials seems even more daredevil than usual. In this video, you can cruise over fountains of lava and watch as it cascades downhill. The perspective on some of these shots is absolutely unreal; it almost seems like it would have to be CGI. (Video credit: Iceland Aerials; via Colossal)

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    Eruption in a Box

    In layers of viscous fluids, lighter and less viscous fluids can displace heavier, more viscous liquids. Here, researchers demonstrate this using four fluids sandwiched between layers of glass and mounted in a rotating frame. (Think of those liquid-air-sand art frames found in museums but bigger!)

    In their first example, each layer of fluid is denser than the one beneath it, so buoyancy forces the lowest layer — air — to rise. The air pushes its way through the more viscous layer of olive oil, then slowly makes its way through the even more viscous glycerin before bursting through the last layer in an eruption. As the team varies the viscosity and miscibility of the layers, the movement of the buoyant fluids through the viscous layers changes dramatically. (Image and video credit: A. Albrahim et. al.)

  • Lava Landscapes

    Lava Landscapes

    Lava flows are, by definition, transient. In his LAVA series, photographer Jan Erik Waider explores the changing vistas and textures of Iceland’s Fagradalsfjall volcano eruption. Using a telephoto lens, he captures incredible details of the charred, cooling outer crust of the lava and the glowing molten interior. Only minutes later, fresh lava tore through, destroying these natural sculptures. You can find prints of his images on his website. (Image credit: J. Waider; via Colossal)

  • Modelling Volcanic Bombs

    Modelling Volcanic Bombs

    When magma meets water on its journey to the surface, the two form a large, partially molten chunk known as a volcanic bomb. As you would expect from their name, these bombs can often be explosive, either in the air or upon impact. But a surprising number of these bombs never explode. Since catching volcanic bombs in action is far too dangerous, researchers modeled them instead to determine what makes a dud.

    Examples of porous volcanic bombs.

    The type of volcanic bomb they were most interested in comes from Surtseyan eruptions, where the bombs travel through shallow sea or lake water, collecting moisture along the way. When the water reaches the molten interior of the volcanic bomb, it flashes into steam. That’s where the pressure to explode the bombs comes from. But the team found that the bombs are also extremely porous, thanks to bubbles created as the magma depressurizes on its trip to the surface. If the bomb is porous enough, steam escapes the rock before it can build to explosive pressures. (Image credit: top – NASA, others – E. Greenbank et al.; research credit: E. Greenbank et al.; via NYTimes; submitted by Kam-Yung Soh)

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    “Stranded”

    The advantage of flying a drone over a volcanic eruption is getting all of the beauty with none of the danger. No asphyxiating on sulfuric gases, no burns from intense heat, no ash or flying rocks. Just the stunning, glowing beauty of fresh earth being born. “Stranded” takes us over and around the recent Icelandic eruption in a way that no human can ever experience. Sit back, relax, and feast your eyes on the spectacle. (Image and video credit: S. Ridard; via Colossal)

  • Lava Fields From Above

    Lava Fields From Above

    Lava flows are endlessly fascinating to watch. They’re a destructive act of creation that seems in many ways familiar; after all, lava moves the same way we see other viscous fluids move. But it’s so much more extreme in its temperature, viscosity, and destructive potential. These beautiful aerial photos by photographer Thrainn Kolbeinsson show the recent eruption at Iceland’s Fagradalsfjall volcano. I love the vivid texture of the lava in these shots and the sharp contrast between the hot and cooling flows. You can see the pahoehoe forming before your very eyes! (Image credit: T. Kolbeinsson; via Colossal)

  • Recreating Volcanic Lightning

    Recreating Volcanic Lightning

    Some natural phenomena, like volcanic eruptions or tornado formation, don’t lend themselves to fieldwork — at least not at the height of the action. The danger, unpredictability, and destructiveness of these environments is more than our equipment can survive. And so researchers find clever ways to recreate these phenomena in controllable ways. The latest example comes from a lab in Germany, where researchers are recreating volcanic lightning.

    To do so, they heat and pressurize actual volcanic ash in an argon environment and let the mixture decompress into a jet, like a miniature eruption. The lightning that accompanies the jet is thought to depend on friction between ash particles, which build up electric charges when rubbed, just like a balloon rubbed against one’s hair. When the charges get large enough, lightning discharges the build-up.

    Small-scale experiments like this one allow researchers to vary the temperature and water content of the ash and observe how this changes the lightning. Drier ash generates more lightning, but it’s hard to distinguish whether this is inherent to the ash or the result of the denser jets that form without the added eruptive force of steam. (Image credit: eruption – M. Szeglat, lab lightning – Sönke Stern/Ludwig-Maximilians-Universität München/Gizmodo; research credit: S. Stern et al.; via Gizmodo)

  • Anak Krakatoa Landslide

    Anak Krakatoa Landslide

    Last December, the collapsing flank of the Anak Krakatoa volcano caused a deadly tsunami in Indonesia. Using satellite imagery, scientists have now constructed a timeline of the island’s dramatic restructuring. In the process, they found that the landslide that triggered the tsunami was likely much smaller than originally estimated.

    Their evidence shows that the landslide and tsunami (Image B) occurred before the eruption that destroyed the volcano’s cone. In fact, the landslide seems to have created a vent that opened directly underwater, which explains the increased violence of the eruption in late December and the eventual destruction of the volcano’s cone (Image C). After that, the underwater vent closed off and the eruption returned to its quieter state as the volcano began rebuilding its cone (Image D).

    The key finding here is that the initial landslide contained roughly a third of the material originally estimated. That means our tsunami models have been seriously underestimating the catastrophic potential of smaller volcanic landslides. Hopefully the lessons we learn from Anak Krakatoa will help us avoid future tragedies. (Image and research credit: R. Williams et al.; via BBC; submitted by Kam-Yung Soh)

  • Volcanic Plume

    Volcanic Plume

    Astronauts aboard the International Space Station captured this dramatic image of Raikoke Volcano’s eruption in late June. This uninhabited Pacific Island is part of the Kuril Islands off mainland Russia. The hot plume of ash and volcanic gas rose until its density matched that of the surrounding air, at which point it could only expand horizontally. This is why the plume appears to have such a flat top. It’s similar to the cumulonimbus clouds we associate with severe thunderstorms. Scientists speculate that the white ring around the plume’s base might be water vapor condensed from ambient air pulled in to the plume’s base or a side-effect of magma flowing into the surrounding sea. (Image credit: NASA; via NASA Earth Observatory)