Sumatran Quake Left 'Scar' on Earth's Gravity

www.livescience.com...

The devastating 2004 Sumatran earthquake, which caused the worst tsunami in modern times, should have left a detectable scar on Earth's gravity field, European scientists said Monday.

A satellite planned for launch next year could detect the blemish, they said.

The magnitude 9.3 earthquake has already been said to have shortened the day by fractions of a second, shifted the North Pole by an inch, and made the planet less fat around the middle.

The new prediction comes from Roberto Sabadini and Giorgio Dalla Via at the University of Milan. The idea is fairly straightforward. The strength of Earth's gravity varies depending on the depth of a trench or height of a mountain, as well as the density of material. Even changing tides alter the gravity field.

The Dec. 26, 2004 quake lifted an 18-foot (6 meter) ledge along a 620-mile (1,000 kilometer) fault.

Gravity variations are measured using the geoid, which is similar to sea-level. The geoid is a hypothetical "surface" around the Earth at which the planet's gravitational pull is the same everywhere. Over dense areas, the geoid moves away from the real surface, and where gravity is less, the geoid moves closer to the real surface.

The Sumatran quake, the geoid moved as much as 0.7 inches (18 millimeters), the scientists predict.

this is amazing!!!

the fact that an earthquake can effect the earth's gravity, that is...

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ENJOY!!!

Amazing is right...interesting indeed!

I'm certain we're going to be seeing many repercussions from the Dec26 quake. I doubt there's a tectonic plate that won't eventually be affected... and the recent spate of volcanic activity is, imo, only a precursor.

Thanks for those great links...

Originally posted by masqua
Amazing is right...interesting indeed!

I'm certain we're going to be seeing many repercussions from the Dec26 quake. I doubt there's a tectonic plate that won't eventually be affected... and the recent spate of volcanic activity is, imo, only a precursor.

Thanks for those great links...

you are right about those plates...

and...

your welcome

It was one helluva quake!

I actually don't find it that hard to believe. It was huge, in a key area, and was really huge. The thing sent the Earth wobbling an extra inch, you don't think it could change a little thing like the geoid? Sending the a huge slab up 1.5 dozen feet is peanuts compared to moving the entire Earth.

Originally posted by Amorymeltzer
It was one helluva quake!

I actually don't find it that hard to believe. It was huge, in a key area, and was really huge. The thing sent the Earth wobbling an extra inch, you don't think it could change a little thing like the geoid?

Sending the a huge slab up 1.5 dozen feet is peanuts compared to moving the entire Earth.

i still find it hard to believe (and amazing) that this quake effected the earth's rotation and our day (maybe about less than a second)...

Originally posted by they see ALL
i still find it hard to believe (and amazing) that this quake effected the earth's rotation and our day (maybe about less than a second)...

Well, what, you figure it was a shifting of the major portions of the Earth's surface, moving tons upon tons of mass all over, and sending shockwaves through the very core of the planet. And, it's frickin' HUGE!

You got some pretty crazy forces adding up there, all sorts of things just flippin' out. It's weird to think about, but when you do, completely possible.