The Japan Earthquake Shortened the 24 Hour Day
By changing the distribution of Earth’s mass, the Japanese earthquake most likely caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds. That’s according to calculations done by Richard Gross of NASA’s Jet Propulsion Laboratory:
The calculations also show the Japan quake should have shifted the position of Earth’s figure axis (the axis about which Earth’s mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth’s figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth’s figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth’s axis in space—only external forces such as the gravitational attraction of the sun, moon and planets can do that.
Great — as if the days weren’t passing by fast enough already!