Earth's days may have gotten a little bit shorter since the massive earthquake in Chile, but don't feel bad if you haven't noticed. The difference is just about one-millionth of a second. ... An earthquake can make Earth rotate faster by nudging some of its mass closer to the planet's axis, just as ice skaters can speed up their spins by pulling in their arms. Conversely, a quake can slow the rotation and lengthen the day if it redistributes mass away from that axis.
Chile earthquake axis rotation spin incredible day