Powerful earthquakes can permanently shorten the length of Earth's day, by moving the spin of the Earth's axis. The 2011 Japan earthquake knocked 1.8 microseconds off our days. The 2004 Sumatra quake cost us around 6.8 microseconds.
I heard about this one but didn't know the exact information. Thank you for sharing:) So two earthquakes cost us 8.6 microseconds!