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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.
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.
In 1993, Stanley Williams survived a close-encounter with a volcano. A volcanologist, he was standing on the rim of Colombia's Galeras volcano when it erupted with little warning. Six of his scientific colleagues and three tourists were killed. Williams fled down the mountain's slope — until flying rocks and boulders broke both his legs. With a fractured skull, he managed to stay conscious enough to huddle behind some other large boulders and dodge flying debris until the eruption ended and his grad students rescued him.
Williams and the other scientists were there to study Galeras, and hopefully get a better idea of what signals predicted the onset of eruptions.
This is something we still don't understand well.
While volcanologists have identified some signals — like distinctive patterns of small earthquakes — that increase the likelihood of an oncoming eruption, those signals aren't foolproof predictions. There are still volcanoes like Galeras that give no warning. And volcanoes like Mt. St. Helens. In 2004, that volcano gave signals that it would erupt. And it did. Sort of. The Seattle Times described it as "two small burps and a lava flow". Basically, the signals don't always precede an eruption, and even when they do happen it doesn't tell you much about how big any ensuing eruption will be.
And that presents an interesting question, writes Erik Klemetti at Wired's Eruptions blog. How close to volcanoes should tourists really be? That's a question with real-world applications. This year, New Zealand's White Island volcano has been ... rather grumbly. Even as tourist boats continued to ferry people over for a view of the crater.
There has always been a fragile relationship between volcanoes and tourism. Volcanic features are some of the most fascinating in the world – just look at the millions of people who visit Yellowstone or Crater Lake National Parks for but two examples of hundreds of volcanic tourist attractions around the world (and that doesn’t even consider all the extinct volcanoes or volcanic deposits that can create amazing landscapes as well). However, with the splendor of volcanic features comes the danger that you, as a tourist, are visiting an active volcano. Sometimes, that danger is low, where either the volcano has been dormant for thousands of years, but the signs of magma beneath are still visible. However, the danger can appear to be low in some places but in reality, you are literally putting your lives in the hands of tour operators when you make the visit.
Read Stanley Williams' account of surviving the Galeras volcano
Photo by Michael Rogers, via GFDL and CC
In the 1990s, archaeologists found a mass grave in London, filled with more than 10,000 skeletons. There have been plenty of things over the centuries that could wipe out tons of Londoners en-masse—the Black Death, famine, fires, you name it. But this grave has turned out to be filled with victims of a far more unlikely natural disaster. Scientists now think those people were killed by a volcano.
Not a volcano in England, of course. But a massive eruption thousands of miles away.
Scientific evidence – including radiocarbon dating of the bones and geological data from across the globe – shows for the first time that mass fatalities in the 13th century were caused by one of the largest volcanic eruptions of the past 10,000 years.
Such was the size of the eruption that its sulphurous gases would have released a stratospheric aerosol veil or dry fog that blocked out sunlight, altered atmospheric circulation patterns and cooled the Earth's surface. It caused crops to wither, bringing famine, pestilence and death.
Mass deaths required capacious burial pits, as recorded in contemporary accounts. In 1258, a monk reported: "The north wind prevailed for several months… scarcely a small rare flower or shooting germ appeared, whence the hope of harvest was uncertain... Innumerable multitudes of poor people died, and their bodies were found lying all about swollen from want… Nor did those who had homes dare to harbour the sick and dying, for fear of infection… The pestilence was immense – insufferable; it attacked the poor particularly. In London alone 15,000 of the poor perished; in England and elsewhere thousands died."
The really interesting bit: Nobody is sure yet where that volcanic eruption actually happened.
Via Cort Sims
So, say you're an Icelandic tour company, with access to an extinct volcano (or, at least, a volcano that hasn't erupted in 4,000 years). And say you want to offer tours inside of said volcano, to tourists who don't have the rappelling experience to get themselves down and up the steep sides of the volcano's crater. How do you do it?
We use a system normally used to carry window cleaners outside of skyscrapers, an open elevator system. A basket that holds 5-6 persons is connected to a crane that has been placed vertically over the crater opening. Massive cable wires move the basket up and down the bottle-shaped vault. The 120 m/400 ft journey takes about 10 minutes to complete.
I really dig this solution!
Inside the Volcano tour, operating in Iceland through August 20.
Via Marilyn Terrell
There are few things quite as tense as watching one volcanologist mutter, "Oh my god. He's crazy. He's crazy," while watching another volcanologist scramble around the edge of a caldera.
It only gets more tense when you realize that the volcano in question is Nyiragongo in the Democratic Republic of the Congo—which has some of the fastest-moving lava flows ever recorded. The key feature of Nyiragongo is that lake of lava in the center of the crater that you see in the video. In January 1977, the lava lake was 2000 feet deep. When the volcano erupted later that month, the lake emptied dry in less than an hour. Lava was clocked at 40 mph.
Here's a story that combines two favorite bits of volcano news into one interesting discovery. You know those great, freaky photos of volcanic lightning? (In case you don't, I've got one posted above.) Remember how the Icelandic volcanic eruptions totally screwed up everybody's airplane travel plans?
Apparently, studying volcanic lightning could lead to better eruption detection systems that could make it easier to predict how big a plume of ash off that volcano will be—knowledge that can help airlines and travelers be better prepared. At Nature, Richard Monastersky reports:
The researchers found that the amount of lightning correlated with the height of the plume, something they could not test using more limited data collected during an eruption at Alaska’s Mount St Augustine in 2006. This observation is important, says Behnke, because systems to monitor lightning could provide an estimate for the size of an eruption, which is not always easy to assess for remote volcanoes.
During a previous eruption at Mount Redoubt in 1989 and 1990, for example, the size of the plume wasn’t known and a plane nearly crashed after passing through the ash cloud and temporarily losing all power from its engines. Behnke and her colleagues suggest that VHF stations similar to the ones they installed at Mount Redoubt could be used to monitor volcanoes to give early warning of an eruption and an estimate of its size.
Via Graham Farmelo
Image: Oliver Spalt via CC