Fingerprinting Slow Earthquakes 23
CarnegieScience writes "The most powerful earthquakes happen at the junction of two converging tectonic plates, where one plate is sliding (or subducting) beneath the other. Now a team of researchers, led by Teh-Ru Alex Song of the Carnegie Institution's Department of Terrestrial Magnetism, has found that an anomalous layer at the top of a subducting plate coincides with the locations of slow earthquakes and non-volcanic tremors. The presence of such a layer in similar settings elsewhere could point to other regions of slow quakes."
Re:Paging all geologists (Score:5, Informative)
Re: (Score:2)
Instead of being a series of rapid movements vertically, sideways, or along the direction of travel, these are going to be extremely slow movements that would take several minutes to complete a single cycle. The energy isn't as damaging, as it is dissipated through friction faster than energy can be transferred by the shaking.
Perhaps I am confused (Score:1)
Re: (Score:2)
Hawaii, Where All the Action Is (Score:2, Informative)
The Pacific Ocean is geologically much more new and deeper than the Atlantic side, which has a much more gradual slope on the continental shelf / continental slope / continental rise subduction system between continents. So we know the Atlantic is older.
Another fun (dynamic) map showing some actual geologic and volcanic activity:
http://oss.zentu.net/?q=node/118 [zentu.net]
Re:Hawaii, Where All the Action Is (Score:4, Interesting)
Re: (Score:3, Informative)
The reason the Pacific Ocean floor is newer is because it's still actively growing quickly as the surrounding plates move away. So while the Atlantic is newer than the Pacific, the *floor* of the Pacific is generally newer than the floor of the Atlantic.
So, in a sense, the parent was correct, but only in a limited sense.
Re: (Score:1)
No, you are right. The reason the Pacific Ocean floor is newer is because it's still actively growing quickly as the surrounding plates move away. So while the Atlantic is newer than the Pacific, the *floor* of the Pacific is generally newer than the floor of the Atlantic. So, in a sense, the parent was correct, but only in a limited sense.
Yes, I did mean the Atlantic coast of the US is older than the west coast / Pacific Rim of Fire side.
I also think it could be reasonably hypothesized that on the Atlantic coast, the gradual slope of the continental shelf / slope / rise could be explained by a longer time period of waves lapping the sediments and such into finer and finer particles. Perhaps explaining how quickly the continents have been drifting apart.
East-coast (of the US) sand is also generally much more fine-grained than west-coast
Re: (Score:2)
Re: (Score:1)
The Pacific Ocean is older than the Atlantic.
The Atlantic formed when Pangaea split [wikimedia.org] (~130 mya). The Pacific ocean is simply what's left from the ancient Panthalassic Ocean [wikipedia.org].
The Hawai'ian Islands are relatively new, though. They're the newest of a long string of (mostly submerged) peaks [wikimedia.org], formed as the Pacific plate drags its butt over a hotspot [wikipedia.org].
Cake (Score:1)
Can we detect this layer in cakes?
Thin end of the wedge (Score:3, Funny)
This is a bad idea.
Soon enough they will start fingerprinting the smart earthquakes. And before long they will be swabbing the mouths of the earthquakes looking for DNA.
Damn! (Score:1)