The recent earthquake in Chile may have messed with the Earth's axis, possibly shortening our days by a whopping 1.26 microseconds, NASA scientists said.
[T]he quake should have moved Earth's figure axis about 3 inches (8 centimeters). The figure axis is one around which Earth's mass is balanced. That shift in axis is what may have shortened days.
Such changes aren't unheard of.
The magnitude 9.1 earthquake in 2004 that generated a killer tsunami in the Indian Ocean shortened the length of days by 6.8 microseconds.
On the other hand, the length of a day also can increase. For example, if the Three Gorges reservoir in China were filled, it would hold 10 trillion gallons (40 cubic kilometers) of water. The shift of mass would lengthen days by 0.06 microsecond, scientists said.