Tokyo quake story

[dakels]

Cnn Story

Just wondering: The story says
"The epicenter of the quake that struck at 01:45 (16:45 GMT) was offshore, 160 kilometers (100 miles) northeast of Tokyo and at a depth of 40 kilometers underwater, according to the U.S. Geological Survey."

Depth of 40km underwater? Well I know no ocean is 40km deep, but even with oceanic crust, most oceanic crust is only about 10km deep. So.... what is this 40km? Misinfo?

 

[blackdogdeek]

maybe they meant 40km below sea level?

 

[Demon-Xanth]

http://earthquake.usgs.gov/eqc.../Quakes/us2008rtbu.php

Nope. Right facts.

 

[dakels]

So what does that mean? Earthquakes can start in the mantle? To my knowledge the deepest area in the ocean is about 10km, and oceanic crust averages about 10km. Anything under that is upper mantle.

 

[Atomic Playboy]

Gojira is restless....

 

[dakels]

Nature article about Deep Focus Earthquakes

Learn something new every day.

 

[MrPickins]

Originally posted by: dakels
Nature article about Deep Focus Earthquakes

Learn something new every day.

Fixed link for ya.

I didn't look at the article, but (IIRC) most deep focus earthquakes are located at subduction zones where a tectonic plate plunges deep into the mantle.

 

[dakels]

Thanks MrPickins.