Fingerprinting Slow Earthquakes

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."

Comments

Paging all geologists

[orclevegam]

Can someone explain WTF a "slow earthquake" is, and why we care? From reading the article it sounds like it has something to do with the speed the compression wave propagates through the crust at, but why that matters I'm not quite sure. No matter what the propagation speed is it's still going to tear things up when it finally does get to you.

Re:Paging all geologists

[b0ttle]

http://en.wikipedia.org/wiki/Slow_earthquake

Re:Paging all geologists

[mikael]

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.

Re:Paging all geologists

[Anonymous Coward]

"The presence of such a layer in similar settings elsewhere could point to other regions of slow quakes." I thought slow Quake was caused by the latency from dial-up. Don't blame any part of the OSI 7-layer model just because you don't have broadband!

Perhaps I am confused

[cwAllenPoole]

Does this mean that the quakes are riding the short bus?

Re:Perhaps I am confused

[mc1138]

Nope, the short buses are riding the quakes!

Re:Perhaps I am confused

[youn]

I'm even more confused... when the quakes play quake... is it doom?

Badsummary

[Anonymous Coward]

"The presence of such a layer in similar settings elsewhere could point to other regions of slow quakes."

So really what you mean is "slow quake areas are indicated by a specific fingerprint", not "fingerprinting these areas slows earthquakes".

Hawaii, Where All the Action Is

[indiejade]

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

Re:Hawaii, Where All the Action Is

[dragonjujotu]

I'm confused, did I learn the wrong thing from all those old science clips that show Pangaea breaking apart and the Atlantic ocean forms as the Americas separate from Europe/Africa?

Re:Hawaii, Where All the Action Is

[Anonymous Coward]

Seriously?! Explain why the Trans-Atlantic ridge is a place of EXPANSION while the Pacific is a region of subduction, which means it's getting EVER SMALLER

Also why all continental history maps show land masses joined where now the Atlantic is!

fucktard.

Re:Hawaii, Where All the Action Is

[khallow]

You can't use the steepness of the continental shelf as a measure of the age of the ocean. The subduction zones around the edge of the Pacific Ocean would greatly steepen the slope.

Re:Hawaii, Where All the Action Is

[Red Flayer]

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.

Re:Hawaii, Where All the Action Is

[panthroman]

The Pacific Ocean is older than the Atlantic.

The Atlantic formed when Pangaea split (~130 mya). The Pacific ocean is simply what's left from the ancient Panthalassic Ocean.

The Hawai'ian Islands are relatively new, though. They're the newest of a long string of (mostly submerged) peaks, formed as the Pacific plate drags its butt over a hotspot.

Re:Hawaii, Where All the Action Is

[indiejade]

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 sand, at least south of the glacial areas of the Great Lakes.

Cake

[KingPin27]

"The presence of such a layer in similar settings elsewhere..."
Can we detect this layer in cakes?

Re:Cake

[Anonymous Coward]

Yes, that is what the Lego Seismograph is used for.

Obligatory

[Anonymous Coward]

In Soviet Russia, the short bus rides YOU!

Thin end of the wedge

[Anonymous Coward]

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!

[Swiper]

Blast my cursory Reading! I thought taking Fingerprints could slow down earthquakes. **rumble**rumble*** hey, we need some more ink over here!!

Just in case...

[Anonymous Coward]

the we ever need to track down an earthquake that committed a crime, or if it decides to strike again!

Just Shut Down HAARP...

[Anonymous Coward]

...would probably be a better way of reducing earthquakes, see: interview with Benjamin Fulford.