In 1991 the dome of the Unzen Volcano in Japan collapsed. This video captures the pyroclastic flow. The running guy's scream is more chilling than the Wilhelm scream.
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A pyroclastic flow is a fast-moving current of hot gas and rock (collectively known as tephra), which reaches speeds moving away from a volcano of up to 700 km/h (450 mph). The gas can reach temperatures of about 1,000 °C (1,830 °F). Pyroclastic flows normally hug the ground and travel downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope. They are a common and devastating result of certain explosive volcanic eruptions.
NOAA just released this awesome NASA image of a volcanic eruption in action. Read the rest
When the volcanic island of Krakatoa erupted in 1883, it "let out a noise louder than any it has made since." Measuring over 172 decibels, it produced "a blast of high pressure air so powerful that it ruptured the eardrums of sailors 40 miles away."
The Sound So Loud That It Circled the Earth Four Times Read the rest
After a peaceful nap three decades long, Mauna Loa seems to be stirring. "While there are no signs of impending eruption, the Hawaiian Volcano Observatory has recorded an increased level of seismic activity on the flanks and summit of Mauna Loa over the past 13 months," reports Big Island Now. "Four distinct earthquake swarms — clusters of earthquakes occurring closely in time and location — have occurred since March 2013."
Mauna Loa is "one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean, [and] the largest subaerial volcano in both mass and volume, historically considered the largest volcano on Earth."
From a Wired Science blog post by Erik Klemetti, assistant professor of Geosciences at Denison University.
As of right now, there is little evidence of deformation or increasing carbon dioxide or sulfur dioxide emissions from Mauna Loa — all key signs that an eruption might be about to start at a shield volcano like Mauna Loa. HVO also notes that the earthquake activity is much less intense now that it was in the years just prior to the 1984 activity. Remember, lava flows from Mauna Loa are definitely a hazard for people living between the volcano and Hilo and Hawaii has been preparing for the volcano’s awakening. Nothing is going on right now, but you can get quite a view from the webcams set up at the Mokuʻāweoweo summit area.
Check out the USGS report, and don't miss out on those webcams. Read the rest
Pyroclastic flows are the infamous deadly avalanches of superheated gas and debris that killed thousands at Pompeii and in the 1902 Mount Pelée eruption on Martinique. Now, thanks to a very brave scientist, you can watch a pyroclastic flow up close.
This is one of several videos taken during the recent eruption of Guatemala's Santiaguito (or Santa Maria) volcano. At the Eruptions blog, Erik Klemetti explains the background of how this footage was made, what it shows, and why it's so important.
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So, when faced with a pyroclastic flow, why would you try to get up close to one? Julio Cornejo, an INSIVUMEH observer from the Santiaguito volcano observatory (OVSAN), did just that to capture some video (see top and below) that has surprised everyone that has seen it. Cornejo was able to film the very far end of a pyroclastic flow generated by the dome collapse at Santiaguito (see above), when it had lost most of its energy but was still moving. At this point a flow is likely still capable of engulfing and suffocating someone in hot ash and gasses, as happened to many people in the 1902 eruption of Mont Pelee. So, Cornejo is very lucky to have made it out alive with this footage, but what he got was remarkable.
Rudiger Escobar Wolf, a volcanology post-doctoral researcher at Michigan Tech who studies volcanoes in Guatemala, posted a sequence of videos from Cornejo and INSIVUMEH and annotated some of the video to understand what we’re seeing. I’ve also watched the video closely and have two here that show some likely never-before-filmed examples of how pyroclastic flows can be destructive even after they slowed to a snail’s pace relative to their usual speed.
[Video Link] There's a video going around that shows a long line of bison trotting down a road in Wyoming's Yellowstone National Park. Some people are pointing to this as a sign that the animals are hightailing it out of the park because the Yellowstone volcano is about to blow its top. But in the video above, Yellowstone Park Public Affairs Chief Al Nash explains that the bison and other animals are simply migrating to a lower elevation where they can find food, which they do every year in the dead of winter.
My takeaway from this video was a reminder that I have a box of mouth-watering Bison Bacon Cranberry Bars in my kitchen cabinet. Read the rest
Image: Tom Pfeiffer/Volcano Discovery
Sicily's Mount Etna volcano is currently erupting. The series of explosions began on October 26, but on November 11, the mountain did something rare and nifty. Over the course of several hours it blew out dozens of perfect smoke rings, each hundreds of feet in diameter, including the one pictured here.
It's not the first time Etna has done this. Nobody knows exactly how the rings form, but people have been photographing smoke rings coming from Etna since at least 1970. Volcanologist and tour guide Tom Pfeiffer took this picture, as well as several others that you can see at his Volcano Discovery website. He suspects that the smoke rings are formed when eruptions alter the shape of volcanic vents. Read the rest
Geology blogger Dana Hunter is putting together some resources that will allow you to take yourself on a fantastic tour of America's most famous volcano
. Includes maps, suggested background reading, and routes that will ensure you get to see the most interesting spots on the mountain — and learn stuff while doing it! Read the rest
Syracuse University makes its own lava by melting down hunks of basalt. Then, they give school kids the opportunity to toast marshmallows over the top of the fiery goo
. Read the rest
At National Geographic, you can read Rowe Findley's 1981 account of surviving the Mount St. Helens eruption
— and his deeply moving profiles of many of the people who did not. Includes this seminal quote from 83-year-old Harry R. Truman, who Findley describes as raising "the adjectival use of profanity to a new high": "It's a part of me, and I'm part of that ______ mountain," said Truman. "If I got out of here, I wouldn't live a _____ day, not a ______ day." Read the rest
It's kind of a "That's no moon" moment in real life — a series of discoveries in the 1960s and 1970s led geologists to realize that most of Yellowstone National Park was one giant volcanic caldera. If you've seen the cable TV specials, you've probably come to the conclusion that an eruption of this supervolcano could doom humanity and that said eruption is bound to happen at any time. But the reality is more nuanced than that, write Annalee Newitz at iO9.com
. Not only is a Yellowstone eruption not imminent, but there's also more than one way it could erupt — and the most likely scenarios don't equate to worldwide horror. Read the rest
National Geographic calls Ethiopia's Danakil Depression "the cruelest place on Earth." It's a desert wasteland, where temperatures can push past 120 F, where ancient and current lava flows impede movement, and where water is so scarce that that people build rock domes over the top of volcanic vents to trap and condense steam.
It's also a place where Ethiopian men and boys regularly travel in order to cut slabs of salt off of the surface of the Earth and haul them back to civilization. Salt flats like this occur when entire bodies of water totally evaporate. In the Danakil Depression, you'll also find salt towers and other formations caused by evaporation off of volcanic geysers and hot springs.
The photo above was taken by Reuters photographer Siegfried Modola, who traveled with a group of salt miners into the desert and then followed their haul all the way back to the marketplace. You can see his full slideshow of images online. I chose this one because it gives you a view of the salt as it's found on the ground, and the neat, rectangular blocks the merchants cut it into for shipping.
The spot is a favorite of photographers. I'd also recommend checking out the photos and story put together by Christina Feldt, who posted about the Danakil salt flats earlier this year. Read the rest
Earlier this month, volcanologists blew 12 holes in an otherwise peaceful meadow in Ashford, New York
. It's not that they had anything against the meadow, per se, it's just that it was a convenient place to do some real-world experiments in how explosions affect the Earth and what we can do to monitor and predict volcanic eruptions. Read the rest
Short answer: We don't know
. What makes this story by Erin Wayman interesting is the way it carefully breaks down an almost Hollywood-ready narrative and finds the fascinating uncertainty lurking underneath. The truth is, uncertainty is cool. Because it means there's more stuff left to discover. Read the rest
On February 20th, 1943, Dionisio Pulido watched as a crack in his farm field collapsed in on itself and began to vomit out ash, rock, and fire. The birth of Mexico's Parícutin volcano is a story I've heard before, but I really enjoyed Dana Hunter's two-part series on the occasion of its 70th volcanaversary. Her posts really get into the perspective of Pulido and other local residents in a way I haven't seen in other accounts, and she does an amazing job of giving you a sense of just how well-documented the birth of this volcano was and why that fact matters so much. Here's Part 1
and Part 2
. Read the rest
The car in this photo was 13 kilometers northeast of Mount St. Helens when that volcano erupted on May 18, 1980. This photo was taken about a month later by researchers from the United States Geological Survey. At the Rosetta Stones blog, Dana Hunter has a really fascinating story — with more eerie photos — about why geologists would want to study totaled vehicles and what we can learn from machines that we can't learn from people. Read the rest
Back in July, I told you about an crane system used to lower tourists
into the now-empty lava tubes of an extinct volcano. Now, you can travel down into Iceland's Thrihnukagigur volcano yourself — via this fascinating video posted at the NOVA website
. While you're probably not getting a view of Thrihnukagigur's magma chamber
, you can see the massive tubes that brought that magma to the surface and stare, gawk-eyed, at the tiny scientists scrambling around inside them. Read the rest