The shift of mass and the massive release of energy slightly altered the Earth's rotation. The exact amount is not yet known, but theoretical models suggest the earthquake shortened the length of a day by 2.68 microseconds, due to a decrease in the oblateness of the Earth. It also caused the Earth to minutely "wobble" on its axis by up to in the direction of 145° east longitude, or perhaps by up to . Because of tidal effects of the Moon, the length of a day increases at an average of 15 microseconds per year, so any rotational change due to the earthquake will be lost quickly. Similarly, the natural Chandler wobble of the Earth, which in some cases can be up to , will eventually offset the minor wobble produced by the earthquake.