Seismicity 2012 so far – Earthquakes Mag 6+ to October 31st
As we trundle on to destruction on 21st December 2012 (NOT!)
I thought it would be a good time to look at the year so far (To October 31).
The charts below are for Magnitude 6 or greater earthquakes using data from the ANSS catalog
Each chart can viewed full-size by clicking on the thumbnail image. They are just too big to show in line.
Earthquakes 2012 to 31st Oct for Magnitude
The next chart shows the same figures, but with depths above the earthquakes. What is particularly curious is that the polynomial trend line of the
magnitudes pretty much matches the polynomial trendline of the depths. I find that somewhat odd and have no explanation for it. By the way as a linear
trend both are completely flat.
Earthquakes 2012 to 31st Oct for Magnitude with depths
Finally the energy output. To be honest tis chart is difficult to read as not only are the numbers very large but the two Magnitude 8+ earthquakes
swamp everything else. I have tried to make it display some part of a bar for every earthquake by setting the bottom of the scale to a negative
Earthquakes 2012 to 31st Oct for Energy
(PS this one is in reverse order)
Converting that energy back to a magnitude the total so far for 2012 is Magnitude 8.72 if it all happened as one single earthquake.
There is a distinctly quieter period in the 'middle' and of later it has got busier, but this is NOT unprecedented. The Northern hemisphere often
produces more earthquakes in the autumn/winter/spring months than it does in the summer. Since the bulk of the world's land mass is in the northern
hemisphere this does skew the figures slightly.
At the end of October we have 119 earthquakes of Mag 6 or greater
12 were Magnitude 7 range and 2 were Magnitude 8 range giving 105 of Magnitude 6 range. I would just add that it is not clear if at least 2 of the
magnitude 6 earthquakes in the list are in fact duplicated from different network sources so the Magnitude 6 range number MAY be 103.
My original estimate for 2012 was
1 x ~8.5
16 x 7.0-7.99
120 x 6.0-6.99
and a total energy output of 600 Petajoules.
Well so far we have 2 Mag 8 so I was wrong on that and this has skewed the energy figure which stands at 771.7 Petajoules. I guess that was a failure
as far as predictions go then!
Other than that we may see a small shortfall on the Mag 7 (I hope) and possibly also a small shortfall on the Mag 6