earthquake shortens days

The magnitude 8.8 earthquake in Chile last Saturday actually shifted the axis of the Earth by 8 centimeters. This led to an increase of the rotation of the Earth, which shortens the days by 1.26 microseconds (0.00000126 seconds). Unfortunately, this can only be calculated, not actually measured. The smallest amount of time that can currently be captured is 5 microseconds.

Now, what does that mean?

Even less sleep for me, I guess.

Sigh.

In comparison to Chile, the 2004 Sumatran earthquake (magnitude 9.1) is estimated to have shortened the length of day by 6.8 microseconds and shifted Earth’s axis by 7 centimeters. It did not have an impact as strong as the one in Chile – JPL research scientist Richard Gross explains why:

First, unlike the 2004 Sumatran earthquake, which was located near the equator, the 2010 Chilean earthquake was located in Earth’s mid-latitudes, which makes it more effective in shifting Earth’s figure axis. Second, the fault responsible for the 2010 Chiliean earthquake dips into Earth at a slightly steeper angle than does the fault responsible for the 2004 Sumatran earthquake. This makes the Chile fault more effective in moving Earth’s mass vertically and hence more effective in shifting Earth’s figure axis.