A '9' is the equivalent of releasing all the worlds energy usage for a year in one go - so really there was no excuse not to warn people - it does'nt get much worse than the equivalent of 20 Trillion Sticks of Dynamite! - The Richter Scale only goes upto 9 it appears:-
Using the Richter and Mercali Scales
Richter Scale The Richter Scale measures the energy of an earthquake by determining the size of the greatest vibrations recorded on a seismogram. On this scale, one step up in magnitude (from 5.0 to 6.0, for example) increases the energy more than 30 times.
Richter Magnitude How many kilograms of TNT would have this much energy?
0 0.6
1.0 20
2.0 600 * Smallest quake people can normally feel
3.0 20 000 * Most people near epicenter feel the quake
* Nearly 100, 000 occur every year of size 2.5 - 3.0
4.0 60 000 * A small fission atomic bomb
* Quakes above 4.5 can cause local damage
5.0 20 000 000 * A standard fission bomb, similar to the first bomb tested in New
Mexico, U.S.
6.0 60 000 000 * A hydrogen bomb; can cause great damage locally
* About 100 shallow quakes of size 6.0 every year
7.0 20 billion * Major earthquake; about 14 every year
* Enough energy to heat New York City for 1 year
* Large enough to be detected all over globe
8.0 60 billion * Largest known: 8.9 in Japan and in Chile/Ecuador
* San Francisco destroyed by 8.25 in 1906
9.0 20 trillion * Roughly the worldÕs energy usage in a year