Definition and characteristics
eruptions happen when lava and gas are discharged from a volcanic vent.
The most common consequences of this are population movements as large
numbers of people are often forced to flee the moving lava flow.
Volcanic eruptions often cause temporary food shortages and volcanic ash
landslides called Lahar.
The most dangerous type of volcanic
eruption is referred to as a 'glowing avalanche'. This is when freshly
erupted magma forms hot pyroclastic flow which have temperatures of up
to 1,200 degrees. The pyroclastic flow is formed from rock fragments
following a volcanic explosion , the flow surges down the flanks of the
volcano at speeds of up to several hundred kilometres per hour, to
distances often up to 10km and occasionally as far as 40 km from the
original disaster site.