What is Digg?30 Comments
- allaboutdatiki, on 01/31/2008, -0/+21They're kind of like farts in that way ...
- vladimus, on 02/01/2008, -1/+10All this and more in the next issue of "Duh" magazine!
- BridgeBurner, on 02/01/2008, -2/+8These scientists must have missed 6th grade science class.
- robwowjo, on 02/01/2008, -0/+5or as mike huckabee might think, it's just God's chess
- inactive, on 02/01/2008, -0/+4Failure.
- inactive, on 01/31/2008, -0/+4Ending in a fartsunami . . .?
- inactive, on 02/01/2008, -0/+3Long live space race. Long live Molvania.
- vaterite, on 02/01/2008, -0/+3You guys are just being silly. Aftershocks are common and well known. The point here is that the major earthquake in this case is a thrust, along a subduction zone (like the Sumatra quake that caused the tsunami). They represent compression, in this case when a subducting tectonic plate moves against and underneath another. Most aftershocks have the same sense of motion as the main quake (down, parallel to the subducting slab), what's weird/cool here is that they claim the main earthquake triggered an extensional quake in the slab, which seems contradictory to the whole idea of thrusting, since the slab is compressing in one place and extending in another. It gives us some idea of the give and take between forces in the crust, and maybe of how deeply water gets incorporated into the slab, which then gets recycled into the Earth's mantle.
- piesforyou, on 02/01/2008, -0/+21. We can measure absolute plate motions using GPS networks (don't laugh, this is very doable and the most common way), using Satellite laser ranging (you bounce a laser off a satellite and compare the difference in the time it takes to receive your signal over time) and by using Very Long Baseline Interferometry (VLBI) - basically you watch how something like a quasar pulses from two different stations on earth. The stations will receive the signal at slightly different times, and this difference will change as the plates move.
2. You can measure finite plate motions, that is, how the plates have moved over a scale of millions of years. There are many ways to do this.
a. The magnetic striping on the ocean floor. Since the earth's magnetic pole undergoes reversals, this is recorded in the oceanic crust that gets accreted at mid-ocean ridges. You end up with a symmetrical pattern either side of the ridge, which can then be dated to determine the speed that the crust is spreading. (incidently, did you know the oldest oceanic crust is barely 200 million years old? Only plate tectonics could explain how that could occur).
b. Correlation of rock units between continents. For example, when the continents came together to form Pangea, the southern margin was within range of glaciers from the south pole. The glaciers formed glacial deposits which are now observed in south america, south africa, australia and india, showing that they must have been much further south and closer together than they are now.
c. The fact that oceanic fracture zones follow small circles around the euler pole of each continent - that is, the point that each continent rotates around, is consistent with plate tectonics.
All of these methods, among others, show that plates DO move, and they move on the order of centimetres per year. This is measurable by GPS. Plate tectonics explains so many aspects of geology, it's a unifying theory which is undoubtedly correct. - motravo, on 02/01/2008, -0/+2"temblor" is a crappy word
- 919kwjc, on 02/01/2008, -0/+1Duh
http://www.youtube.com/watch?v=SdKQKovdP3E - theVariable, on 02/01/2008, -1/+2Captain Obvious saves the day, once again.
- CuddyBuddy, on 02/02/2008, -0/+1Hmmm...when it rains, it pours doesn't it!
- inactive, on 02/01/2008, -1/+2Tectonic chess
- Asianwaste, on 02/01/2008, -0/+1Muppet Babies put it best: It's the Earth burping. Ms. Piggy will put a stop to it thus dooming us all.
- uker, on 02/01/2008, -0/+1natural disaster has silencing power. http://www.chineselives.info/2008/01/28/ice-rain-t ...
- OwdenBowden, on 02/01/2008, -0/+1It is like trowing a pebble into a pond. One ring creates another when it expands and eventually the energy wave depletes and we start all over again.
- piesforyou, on 02/01/2008, -0/+1Did you even RTFA? This is about how a rupture on a compressional, thrust fault can actually trigger the rupture of a normal fault - which is extensional. This builds on our knowledge of earthquake hazards in a subduction setting, is new research, is not common sense and hence why it was in Nature - which is THE place to get your paper published.
- piesforyou, on 02/01/2008, -0/+1You must have missed the bulk of the article.
- troon, on 02/01/2008, -0/+0Never mind that - I want to know why really big earthquakes tend to occur on 26 December.
- inactive, on 02/01/2008, -1/+1Yes.
- retzed, on 02/01/2008, -0/+0Or like one fat person falling into another fat person.
- antechinus, on 02/01/2008, -1/+1Would you care to prove that plate tectonics is a real planetary mechanism on Earth.
- troymccluresf, on 02/01/2008, -2/+1Don't worry, Kim Delaney and Tony Almeida will save us!
- phaeton99, on 02/01/2008, -1/+0Science? I thought this was about Rosie O'Donnell and Roseanne Barr.
- inactive, on 01/31/2008, -7/+4Or they could be caused by your mom falling out a chair...........
- robwowjo, on 01/31/2008, -6/+3Yay science!
I think earthquakes are an amazing phenomena for sure, shows how fragile the earth can be!
I knew about aftershocks, but back up info is useful!
still, cool though - wukillabee, on 02/01/2008, -6/+1I, for one, welcome our new super earthquake overlords
- Blitzenn, on 02/01/2008, -10/+3OMG! I wonder how much those guys got paid to explain COMMON SENSE to everyone and make up new words to do it. I think we should fire every 'scientist' who thinks this was some sort of discovery or breakthrough in understanding. Stop paying them now, please! It's just expensive stupidity.
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