National Geographic has an interesting article on a phenomenon known as earthquake lights where scientists have apparently made some headway into determining the cause.
Rare flashes of light that are sometimes seen around earthquakes are not caused by birds, or planes, or UFOs—all of which had been previously used to explain the phenomena known as earthquake lights.
Instead, the lights are caused by electrical properties of certain rocks in specific settings, report scientists in a new paper.
Sometimes called earthquake lightning, the lights can take "many different shapes, forms, and colors," says study coauthor Friedemann Freund, an adjunct professor of physics at San Jose State University and a senior researcher at NASA's Ames Research Center.
Freund says common forms of earthquake lights include bluish flames that appear to come out of the ground at ankle height; orbs of light called ball lightning that float in the air for tens of seconds or even minutes; and quick flashes of bright light that resemble regular lightning strikes, except they come out of the ground instead of the sky and can stretch up to 650 feet (200 meters).
(Score: 5, Funny) by Non Sequor on Tuesday February 03 2015, @12:04AM
Nothing to see here. Please move along.
Write your congressman. Tell him he sucks.
(Score: 3, Interesting) by DeathMonkey on Tuesday February 03 2015, @06:21PM
How the fuck do you Disagree with a joke.
(Score: 2, Disagree) by frojack on Tuesday February 03 2015, @12:43AM
I had some quartz looking rocks (thumb little stones) that I bought somewhere that would spark externally and internally when tried to scratch one with the other, using quite a bit of force. You could see the spark little ways below the surface because it was a crystalline structure.
Do you suppose something like this on a grand scale could cause something like the described events?
No, you are mistaken. I've always had this sig.
(Score: 0, Disagree) by Anonymous Coward on Tuesday February 03 2015, @12:46AM
I was wondering the very same thing. I had some quartz rocks that would spark in the same manner when you hit one with the other.
(Score: 5, Informative) by Anonymous Coward on Tuesday February 03 2015, @01:00AM
I was wondering the very same thing.
Sigh...
I know it's too much to ask, but since TFA specifically says it's not likely to be piezo, (since piezo doesn't generate enough energy) maybe you could look a little further before commenting?
Anyway, for the terminally lazy, here's the Wikipedia entry:
The most recent model suggests that the generation of earthquake lights involves the ionization of oxygen to oxygen anions by breaking of peroxy bonds in some types of rocks by the high stress before and during an earthquake. After the ionisation, the ions travel up through the cracks in the rocks. Once they reach the atmosphere these ions can ionise pockets of air, forming plasma that emits light. Lab experiments have validated that some rocks do ionise the oxygen in them when subjected to high stress levels.
TLDR: Ionization is causing plasmas
(Score: 1, Disagree) by khallow on Tuesday February 03 2015, @02:02AM
I know it's too much to ask, but since TFA specifically says it's not likely to be piezo, (since piezo doesn't generate enough energy) maybe you could look a little further before commenting?
Except that the original poster did demonstrate a piezo effect (generating visible sparks from mild handling of the rock) which when scaled up to an earthquake zone would have enough energy.
(Score: 1, Informative) by Anonymous Coward on Tuesday February 03 2015, @02:16AM
Bad Theories of Earthquake Lights
It is clear that somehow, subterranean stress in an earthquake zone is transformed into a luminous phenomenon in the surroundings. Most of the theories proposed are unconvincing.
Heat: Friction on the fault might heat particles or ignite ground gases. But the heat would not move swiftly, nor would it occur without earthquakes, nor is there enough gas (such as methane) in most places.
Radiation: Radon gas is released by fractured mineral grains and could ionize the air, but the quantities are too small.
Triboluminescence/triboelectricity: Some minerals respond to mechanical strain by generating light or electric charge—but not enough of either.
Piezoelectricity: Quartz crystals generate voltage under strain—but not enough, and the resulting currents cancel out in real rocks, and besides rocks are electrical insulators.
Streaming potentials: Moving fluids in narrow cracks tend to become electrically charged—but not strongly.
http://geology.about.com/od/earthquakes/a/EQlights.htm [about.com]
This might also be helpful:
Google Search
From Wikipedia, the free encyclopedia
Google Search, commonly referred to as Google Web Search or just Google, is a web search engine owned by Google Inc. It is the most-used search engine on the World Wide Web, handling more than three billion searches each day.
http://en.wikipedia.org/wiki/Google_Search [wikipedia.org]
(Score: 4, Interesting) by khallow on Tuesday February 03 2015, @07:24AM
(Score: 4, Insightful) by TheLink on Tuesday February 03 2015, @06:49AM
I think there are many explanations, and saying it's finally explained and that it's not piezo is too simplistic.
After all how does ionized gas from cracks in rocks explain lights in the sky? I would expect that ionized gas would react ASAP with whatever they come into contact with. It might explain the flames from the ground and maybe glowing balls near the ground ( http://www.newscientist.com/article/dn24886-natural-ball-lightning-probed-for-the-first-time.html#.UthoYWRDuB4 [newscientist.com] )but not the other stuff.
I think some lights in the sky might be more like a localized aurora where the local magnetic field is being reduced so that an aurora can appear there.
Other lights in the sky might be due to geomagnetically induced electric fields in clouds generating lightning: https://www.youtube.com/watch?v=VBwXR_It9kw [youtube.com]
(Score: 0) by Anonymous Coward on Tuesday February 03 2015, @07:06AM
I still think aliens are responsible ;)
(Score: 4, Funny) by Anonymous Coward on Tuesday February 03 2015, @03:17AM
Rocks producing electro-plasma? Must be dilithium.
(Score: 4, Informative) by mcgrew on Tuesday February 03 2015, @06:32PM
TFS mentions ball lightning, it should be pointed out that most times when ball lightning is seen there is no earthquake, but rather a thunderstorm. Wikipedia [wikipedia.org]
It was raining really hard the one time I saw ball lightning. Pretty cool phenomenon.
Carbon, The only element in the known universe to ever gain sentience