Did Quake Speed Earth's Spin?

LOS ANGELES -- The deadly Asian earthquake may have permanently accelerated the Earth's rotation -- shortening days by a fraction of a second -- and caused the planet to wobble on its axis, U.S. scientists said on Tuesday.
Richard Gross, a geophysicist with NASA's Jet Propulsion Laboratory in California, theorized that a shift of mass toward the Earth's center during the quake on Sunday caused the planet to spin 3 microseconds, or 3 millionths of a second, faster and to tilt about an inch on its axis.
When one huge tectonic plate beneath the Indian Ocean was forced below the edge of another "it had the effect of making the Earth more compact and spinning faster," Gross said.
Gross said changes predicted by his model probably are too minuscule to be detected by a global positioning satellite network that routinely measures changes in Earth's spin, but said the data may reveal a slight wobble.
The Earth's poles travel a circular path that normally varies by about 33 feet, so an added wobble of an inch is unlikely to cause long-term effects, he said.
"That continual motion is just used to changing," Gross said. "The rotation is not actually that precise. The Earth does slow down and change its rate of rotation."
When those tiny variations accumulate, planetary scientists must add a "leap second" to the end of a year, something that has not been done in many years, Gross said.
Scientists have long theorized that changes on the Earth's surface such as tide and groundwater shifts and weather could affect its spin but they have not had precise measurements to prove it, Caltech seismologist Hiroo Kanamori said.
"Even for a very large event, the effect is very small," Kanamori said. "It's very difficult to change the rotation rate substantially."

Speed Of The Earth

How Fast Does The Earth Obit The Sun and Rotate On Its Axis ?
The earth rotates on its axis once each day. Since the circumference of the earth at the equator is 24,901.55 miles, a spot on the equator rotates at approximately 1037.5646 miles per hour (1037.5646 times 24 equals 24,901.55) (1669.8 km/h).
At the North Pole (90 degrees north) and South Pole (90 degrees south), the speed is effectively zero since that spot rotates once in 24 hours, a very, very slow speed.
To determine the speed at any other latitude, simply multiply the cosine of the degree latitude times the speed of 1037.5646.
Thus, at 45 degrees north, the cosine is .7071068 so multiply .7071068 times 1037.5464 and the speed of the rotation is 733.65611 miles per hour (1180.7 km/h).
For other latitudes...

10° - 1021.7837 mph (1644.4 km/h)
20° - 974.9747 mph (1569.1 km/h)
30° - 898.54154 mph (1446.1 km/h)
40° - 794.80665 mph (1279.1 km/h)
50° - 666.92197 mph (1073.3 km/h)
60° - 518.7732 mph (834.9 km/h)
70° - 354.86177 mph (571.1 km/h)
80° - 180.16804 mph (289.95 km/h)

In addition to the rotational speed of the earth spinning on its axis, the earth is also speeding at about 66,660 miles per hour (107278.87 km/h) in its revolution around the sun once ever 365.2425 days.