Now those are what I call aftershocks!

There have been a few earthquakes near the north coast of Papua, Indonesia, some rather big ones in fact, but thankfully none have posed a tsunami risk to us.

Earthquake magnitude is a logarithmic measure of earthquake size. In simple terms, this means that at the same distance from the earthquake, the shaking will be 10 times as large during a magnitude 5 earthquake as during a magnitude 4 earthquake. The total amount of energy released by the earthquake, however, goes up by a factor of 32. Now check out these magnitudes, courtesy of the US Geological survey. Times are in NZ Daylight Savings Time.

January 4 2009

07:43am- 7.6
08:47 - 4.8
09:30 - 5.1
09:41 - 5.6
10:07 - 5.2
10:23 - 5.0
10:33 - 7.3
11:01 - 5.2
12:00noon - 5.4
12:05pm - 5.3
12:55 - 5.1
01:55 - 5.3
02:29 - 4.7
02:47 - 4.8
03:28 - 4.9
05:44 - 5.4
06:05 - 4.9
06:53 - 4.7
07:14 - 6.0
07:33 - 5.1
08:12 - 4.9
08:54 - 4.3
11:08 - 4.6
11:49 - 5.0

January 5 2009
01:06am - 4.8
01:10 - 4.8
03:43 - 4.6
05:13 - 4.7

Those are some big aftershocks, and not knowing whether the next one is going to be worse or less than the previous one has to be terrifying!