Sometimes before an earthquake, strange bright orbs and glows are seen in the sky, like the scene visible in this video clip captured a half hour before the 2008 quake in Sichuan, China. You might think these are related to the UFOs that cause the quakes, but new research not only suggests a natural cause but also raises the possibility that the phenomena could be an indicator that a quake is coming. The scientists from Quebec Ministry of Natural Resources and San Jose State University suggest that rocks under high stress deep underground release oxygen ions that eventually make their way to the surface, ionizing air pockets above ground and creating a light-emitting plasma.
“If you see visible lights in the sky, and you live in an earthquake-prone area, they might be an early-warning sign that an earthquake is approaching,” geologist Robert Thériault says.
More in Smithsonian: "Why Do Lights Sometimes Appear in the Sky During An Earthquake?"
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.
How does Google Maps account for plate tectonics?
That's the seemingly simple question that led George Musser to unearth some fascinating facts about map-making, history, and the accuracy of modern GPS systems. Turns out, not only does the crust of the Earth, itself, move, but so do the locations of lines of latitude and longitude. Both those things contribute to small errors when your GPS tries to pinpoint exactly where you are. — Maggie
Today at i09, geophysicist John Bellini will be answering your earthquake-related questions
, starting at 12:30 Pacific time. — Maggie
This image shows magnetic anomalies in the South Pacific — underwater lines where the crust of the Earth either matches up with the planet's overall magnetic polarity (reds and purples) or is completely reversed (blues). Invisible to the naked eye, these stripes run along all of Earth's ocean basins. We first noticed them in the 1950s and, at first, they were a giant mystery. Why would there be these distinct lines of magnetism, and why would the lines fluctuate in their polarity? As Chris Rowan explains at the Highly Allochthonous blog, the answer ended up being a key part of proving that chunks of the Earth's crust were moving away from each other.
Fred Vine and Drummond Matthews thought through the consequences of the hypothesis put forward by Harry Hess, that new oceanic crust was being continuously produced by the eruption of basalt at mid-ocean ridges. When combined with the facts that newly cooled basalt has a strong remanent magnetisation aligned with the ambient magnetic field, and that the Earth’s magnetic field reverses its polarity every million years or so. Vine and Matthews* argued that if seafloor spreading was indeed occurring at mid-ocean ridges, then linear positive and negative magnetic anomalies, formed from crust produced in normal and reversed polarity chrons, would form a symmetric pattern around the mid-ocean ridges, which is exactly what we see.
Scientists using radio waves to estimate the thickness of the ice sheet that covers Greenland found a canyon
— more than 2600 feet deep and almost 500 miles long — buried under the ice. Longer than the Grand Canyon, the Greenland canyon hasn't ever been seen by humans. It was probably last completely uncovered 4 million years ago. — Maggie
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! — Maggie
A week ago, Randall Munroe finished "Time", XKCD's long, running, slow-updating, 3,000+ frame comic telling the story of two people who discover an impending superflood that would destroy their society. Randall's explained in detail what was going on there, from the geology of the thing (it's set millennia in the future, amid a civilization denied the ability to jumpstart itself by the paucity of remaining fossil fuels, and the flood is modelled on a real event that sealed off the Mediterranean Sea five million years ago) to the fictional language the upland culture speaks (designed by a linguist, and still mysterious).
Read the rest
A slope may look stable, but that doesn't mean it will always be
stable. The same geologic material can, under certain circumstances, lose its strength and integrity. Here, a geologist demonstrates how this might happen with the help of a tired kitteh
. — Maggie
In the 1870s, a French geographer proposed digging a canal from the Mediterranean to flood a low-lying part of the Sahara Desert
. He pitched it as good for business and good for local environments, writes Ron Miller at i09. But I can't help but think of Plagues and Pleasures of the Salton Sea
— a documentary about the development, culture, and slow, ongoing destruction of a salty, inland sea
that accidentally formed in southern California in the first part of the 20th century. — Maggie
Mars' landscape was formed by flowing water, and the proof is in the pebbles
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. — Maggie
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. — Maggie
Geoscientist Matt Kuchta explains why wet sand makes a better castle than dry sand — and what you can do to make your sand fortress even more impenetrable. Hint: The secret ingredient is window screens.
Dry quicksand was a mythical substance — normal-looking sand that could swallow you in a flash. That is, until 2004, when scientists made the stuff in a lab. (Mark told you about that development.)
In this video, geologist Matt Kuchta explains how dry quicksand is different from both wet quicksand and stable sand. Hint: Think "Jenga".