okay, that's just freaky.
Sumatran Quake Left 'Scar' on Earth's Gravity
By LiveScience Staff
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.