- Education and Science»
- Geography, Nature & Weather
Living on the Edge-Where the Volcano Sleeps...or Erupts? the Vesuvius Eruption, the Krakatoa Eruption and More Hot Stuff
History of the deadly volcano
Volcanic eruption have been a fact of life since the earth first formed as a solid planet, and they have taken a huge toll of human life over the centuries. One of the earliest recorded disasters was the Vesuvius eruption in AD 79 which buried the Italian city Pompeii under ash, killing an estimated 16,000 people. You can still see the power of ash, the shocking 'sculptures' if you visit the Archaeological Museum of Naples, where these beautiful but sad artifacts are kept. The most violent eruption of modern times was in Krakatoa, Indonesia, in 1883, when more than 36,000 people were killed and derbis was scattered across the Indian Ocean as far away as Madagascar, off the east of Africa.
The arsenal of Mother Nature
There are about 500 active volcanoes in the world today, thought it is always unsafe to assume that any volcano is on the retired list. The types of eruption vary greatly. The simplest kind, found in Hawaii and Iceland, is a more or less continuous fountain of fire, sometimes reaching incredible heights. Next in order of complexity are eruption that follow the Stromboli pattern, where the lava is less fluid and the rate of eruption is not so high- from one every few seconds to one every couple of hours.
But even well-behaved volcanoes can turn nasty if water gets into them. It boils to produce steam and this increases explosive power. When a section of rain sodden ground fall into Mount Etna, in 1979 blocking the flaw of lava, pressure built up so much that when it was released the huge explosion killed nine tourists who were peering inside.
Even more dangerous is the nuee ardente (a burning cloud), which occurs in volcanoes where the lava is viscous and rich in gas. Pressure builds up gradually and imperceptibly, though towards the end a distinct swelling of the mountain may be detected, as if it is getting ready to give birth. When the eruption finally happens, the gas is released like the fizz in a well-shaken bottle of champagne throwing out a mass of dust, ash and solid chunk of lava at speed of up to 100km/h and at temperatures 100 and 900 degree C. the hot gases destroy the delicate tissues of the lungs, which can no longer absorb oxygen from the air. Death is by suffocation.
Researchers about volcanic eruptions
Studies by vulcanologists show that there is no real evidence of an accelerating pace in the number and frequency of eruptions, but that increasing world population mean that when a volcano does erupt, it may well affect more people. In fact, this is already happening. The eruption of Pinatubo, in the Philippines, in 1991 has affected the entire world population. More than a year after the eruption, a belt of ash and chemical still circles the Equator at an altitude of about 30 kilometres, disrupting the ozone layer of the planet’s climate.
We have yet to see the full capacity for devastation of a volcanic eruption in the modern world. If a major eruption were to occur in Japan, New Zealand or California, as is possible in the near future, we might be counting the dead in millions rather than tens of thousands, and looking at the destruction of a nation’s economy and serious destabilisation of the world power rather than the loss of a few billion dollar.