Gus > Not as initially measured by the Jakarta Seismographic Institute
As I understand it, the reason for the "upgrade" is because Richter magnitude 9 is full scale on the seismometer and grades higher than 9 are achieved not just by deflection but by how long the full-scale oscillation persists. So, to some extent it depends on consensus between various stations.
Anyway, here's another measure of earthquake intensity:
usask.ca
>>Radiated seismic energy is estimated by log(E) = 4.4 + 1.5 * M where E is energy in joules, and M is surface wave magnitude. For a M8 earthquake this works out to about 7 billion kilowatt-hours. This is more than the total electric consumption of Canada in one day. Unfortunately, the energy is released in a few seconds, not hours, so the power of a 30 second M8 earthquake is more than a thousand billion horsepower.*** A kilowatt is 1.34 horsepower. If the area of strong shaking measures 200 km by 100 km, there are about 25 horsepower applied to every square metre during that 30 seconds, with more near the centre, and less near the edge.
Energy released in a large earthquake is immense, much greater than all the energy of all the smaller magnitude earthquakes in the area. Consequently, small earthquakes are not effective in releasing energy so as to prevent a large earthquake. <<
*** and if log 9 is ten times log 8 then a magnitude 9 earthquake will release more power than Canada consumes in ten days -- and all in a few seconds. Perhaps you may now accept that that is a tall order for anyone including the omnipotent Judeocons who I agree can do most things -- even enlist the power of God, himself. |
