A very nice animation of the 2011 worldwide seismicity for earthquakes M ≥ 4.5 in the following link http://www.youtube.com/watch?v=cwWn_W6ZbT4&feature=youtu.be (with sound intensity for each earthquake plotted on an orthographic globe map).
In 2011, we experienced 205 earthquakes with M ≥ 6.0, and 9.323 events with M ≥ 4.5. Watch how nicely the plate boundaries are inferred even with one year of seismicity data. Have a look also towards the last two minutes of the animation where you can observe the profound effect of the 11thof March 2011 Tohokou Mw=9.0 Japan earthquake on the seismicity data.
You can clearly see that the Tohokou aftershock activity and the earthquake triggering effects have significantly increased the total number of earthquakes worldwide. This shows nicely that earthquakes do not occur randomly in time (as the probabilistic Poissonian model assumes). This is why in probabilistic seismic hazard assessment the aftershock activity is extracted from the catalogues, but this introduces an additional source of uncertainty.
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