Two volcanoes are active in the Western hemisphere at the moment: Mount Sangay in Ecuador, where two British explorers have just lost their lives in an eruption; and La Soufriere, some 1,800 miles (3,000 kilometres) to the north-east, on Guadeloupe in the Caribbean.
Two volcanoes are active in the Western hemisphere at the moment: Mount Sangay in Ecuador, where two British explorers have just lost their lives in an eruption; and La Soufriere, some 1,800 miles (3,000 kilometres) to the north-east, on Guadeloupe in the Caribbean. Here, ash has been raining down on the banana plantations since the volcano burst into activity last Monday night (16 August) and about 70,000 people have been evacuated from their homes. The scientists predict that a massive explosion is yet to come.
SYNOPSIS: Volcanoes--gaps in the earth's crust through which gas and molten rock burst out--may occur anywhere; but most of those still active are in a huge belt encircling the Pacific Ocean. This one appeared for the first time last year on the Kamchatka peninsula in the Soviet north-east and broke al local records for its violence and intensity.
Kilauea, in Hawaii, is known for its thin, fast-moving lava. The traffic markings can just be seen on a main road as the lava poured over it in the 1970 eruption.
Anything in its path that will burn catches fire -- for the temperature of the lava is often more than 1,000 degrees centigrade when it reaches the earth's surface.
In the Philippines in 1968, heavy rain followed the eruption of the Mayon Volcano and turned the ash into a stream of mud. This dried out into a solid cake that had to be chipped away. The rain as well as the ash had been caused by the eruption; it came from the condensation of escaping steam.
In Africa, most of the volcanoes are in the region of the Great Rift valley, on the eastern side of the continent. This is Nyamuragira, on the eastern border of Zaire, erupting in 1971.
The lava, flowing down at a speed of 10 miles (16 kilometres) an hour covered a strip of land a mile (1 1/2 kilometres) wide. Luckily in this case there was no danger to any villages. The nearest were on the opposite side of the crater from the flow.
Kirkjufell in Iceland had been thought to be extinct. Then, in 1973, it suddenly erupted--apparently for the first time in 7,000 years. The fishing port of Vestmannaeyjar was left thick in black ash; and even worse for the economy, the harbour was partly blocked by lava. In most recent eruptions, there has been enough warning to get people in danger evacuated. The most serious effect has therefore been the material damage.
People who live around Mount Etna in sicily are no strangers to the fear of another eruption. Well over a hundred have been recorded in the past 2,000 years. The last big one was in 1971, and the trail of damage can still be seen. Ironically, the lower slopes, built up by the earliest eruptions, are extremely fertile, drawing people back to cultivate vines, olives and fruit.
The most dangerous eruptions re those which produce "glowing avalanches" -- clouds of incandescent dust which move extremely fast and can wipe out a town in a few minutes. This happened in 1902 in Martinique, just south of the now-threatened island of Guadeloupe.