had thought that Krakatoa in 1883 was the most violent recorded eruption and the most devastating......
You could be right RF, I dont know - I was always under the impression it was Tambora, if anyone can clarify then please do.
Eruptions are classified by their VEI or Volcanic Explosivity Index. Krakatau explosion of 1883 was VEI 6 whists Tambora`s 1815 was a VEI 7. Both of them are nothing compared with Toba`s 77,000 BC explosion of VEI 8.
The VEI is not an arithmetic escalation but a geometrical one: a VEI 1(Strombolian), for example produces an ejection of tephra of less than 10,000 m3 with a plume of some 100-1000 meters. A VEI 3 (Vulcanian), like those of my country`s volcanoes, are of 10,000,000 m3 of tephra expelled and with plumes of 15 km. A VEI 4 (Pelean) like the one of Mount Peleè at Martinique in 1902 that killed some 30,000 persons expells some 0,1 km3 of tephra with a plume of 25 km. The famous eruption of Vesubius that destroyed Pompei in 79 BC was a VEI 5 (Plinian) with 1 km3 of tephra and a plume of more than 25 km. Mount Saint Hellens 1980 eruption was equivalent to Pompey`s one. A VEI 6 is Krakatau`s one with an expulsion of more than 10 km3 and a plume of 25 km. VEI 7 ejects more than 100 km3 of tephra whilst the Ultra Plinian erution VEI 8 represents 1,000 km3 of tephra. There has been no VEI 8 eruptions in historical records but scientists estimated that at least one occured every 1,000 years (for VEI 7) and 10,000 years (VEI 8). There are 5 registers of VEI 7 in the last 10,000 and 0 in for VEI 8. That means that maybe our grandchildren will witness one of those and, very certainly, we or our sons will see Vesubius`in one of it´s VEI 5 explosions.
There is a very interesting article in Wikipedia on this:
http://en.wikipedia.org/wiki/Volcanic_e ... _eruptions
I hope you will enjoy this. I love volcanoes, however I´m praying for the one I live on not to do anything stupid during my lifespan.
Regards