There are literally hundreds of volcanic eruptions each year around the globe. Most are minor. But, we’re way over due for something like the Toba Supervolcano that started us on our way to the last ice age known here on earth- that lasted some 50,000+ years. No small event. Of course super volcanoes are in a class by themselves and we can only pray that we don’t experience one in our lifetime, even though the next one most probably sits right here in the United States.
Just to name a few of the types of volcanoes, let’s begin with what we don’t see. First of all there are the Subglacial volcanic eruptions are named because of activity under ice, or under a glacier. They can cause dangerous floods and create hyaloclastite and pillow lava. While they are few and far between they exist. Ask your travel agent the next time you take a cruise to the Artic.
Secondly, we have what’s known as the Strombolian volcanic eruptions which are named because of activity of Stromboli in Sicily. They are characterised by huge clots of molten lava bursting from the summit crater to form luminous arcs through the sky. Collecting on the flanks of the cone, lava clots combine to stream down the slopes in fiery rivulets. The explosions are driven by bursts of gas slugs that rise faster than surrounding magma.
Thirdly there are the Vulcanian eruptions which are characterised by a dense cloud of ash-laden gas exploding from the crater and rising high above the peak. Steaming ash forms a whitish cloud near the upper level of the cone.
Fourthly we have the second most powerful volcano type known as the Plinian eruptions which involve the explosive ejection of relatively viscous lava. Large plinian eruptions— such as during 18 May 1980 at Mount St. Helens or, more recently, during June 1991 at Pinatubo in the Philippines— can send ash and volcanic gas tens of miles into the air. The resulting ash fallout can affect large areas hundreds of miles downwind. Fast-moving pyroclastic flows are also commonly associated with plinian eruptions.
And then we have the Super Volcanoes, not to be confused with the super delegates or super Tuesday. Scientists believe the next one to happen (in our life time) would be the Yellowstone Supervolcano.
In terms of power, the Mount St. Helens was a VEI 5 (volcanic explositivity index) The largest eruption in modern time was the VEI 17 explosion at Tambora, Indonesia in 1816 that killed a little less than 100,000 people. It changed the weather for years. In fact, 1816 is known as the “year without a summer” in Europe.
What worries scientists most though is that we’re now coming to realize that (as far back as we can go) volcanic eruptions are caused by sun spot activity and guess what. The next maximum sunspot activity for this elven year cycle is to occur in 2012.
But, don’t worry, you won’t have to wait until December 21, 2012. There will be enough build up between now and then to give a a warning. But, a warning to do what exactly? And you’re worried about global warming?
