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SECTION 1
INTRODUCTION   
INSIDE THE EARTH
WHAT R VOLCANOES

SECTION 2
NATURE OF VOLC'S
PRINCIPLE TYPES
OTHER STRUCTURES
ERUPTION TYPES

SECTION 3
FAMOUS VOLCANOES
LATEST ERUPTIONS
SUBMARINE VOLC'S
VOLC'S IN THE SOLAR
GAYSERS......

SECTION 4
ENVIRONMENTS
PLATE TECTONICS
PLATES MOVING
EXTRATERRESTRIAL
MONITORING

 

SECTION 5
PEOPLE & VOLC'S
PROTECTION
PREDICTING

SECTION 6
GLOSSARY
CONTACT

 

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FAMOUS VOLCANOES

MOUNT.ST.HELENS

Since its eruption in May 1980, Mount St Helens has become the best know of North America’s Volcanoes. Before 1980, St Helens was just another of the line of snow-clad cones that stretch along the United States’ Pacific coast. It was distinguished by its fine, symmetrical shape, in market contrast with the gnarled peaks of its neighbours Mount Rainer and Mount Adams. In early 1980, St Helens began to pour from fractures near the summit. The snow began to darken as rock fragments became caught up In the violence of the explosions, and a small crater began to form and deepen near the summit.

During April and early May 1980, the northern side of the volcano began to push out, bulging under the pressure of the molten rock beneath. On the morning of May 18, a moderate earthquake proved to be the final straw. The ‘bulge’ slid off the volcano’s side, triggering a massive explosion. Over the course of the next couple of minutes, a blast of hot ash raced across six hundred square kilometers of prime forest, tossing trees aside like matchsticks. For the rest of the day, a column of ash and pumice rose twenty kilometers above the volcano. Ash rained out across the northwestern states. The top four hundred meters of the volcano was replaced by a gaping grey amphitheatre. For the next six years, a small dome of lava pushed its way out into the new crater, until gradually the conduit was plugged and activity stopped. In all, about one cubic kilometer of rock was thrown out during the whole eruption.

Mount St. Helens was a tiny eruption by global standards. Yet it taught us a lot. Until St Helens, nobody realised quite how fragile volcanic mountains are. Since then, numerous examples of volcanoes that have collapsed sideways have been recognized from the telltale carpet of hummocks and hills that stretch away from the remains of ancient amphitheatres. St Helens also gave an inkling of nuisance that even a small eruption can cause to a society that relies on sensitive equipment for transport, communications and day-to-day life.

 

 

 

 

 

 

 

 

 

View south along west arm of Spirit Lake to the decapitated Mount St. Helens in 1983. Part of the gigantic landslide (debris avalanche) that removed the former summit swept entirely through Spirit Lake (hummock in foreground), causing a tsunami to sweep as high as 250 m (820 ft) above the lake.


KRAKATAU, INDONESIA

            In May 1883, ash, gas and pumice erupted from a volcano on the Indonesian island of Krakatau. The island is located in an unstable area where the Indo-Australian plate sub ducts under the Eurasian plate. The early rumblings form the volcano were just warm-ups before the violent explosion that blew the island apart on 27th August. The boom from the explosion, one of the loudest ever recorded, was heard 3500 kilometers (2170 miles) away. Clouds of dust and ash rose 80 kilometers (50 miles) into the air, circled the globe, and created many colorful sunsets around the world. As the volcano collapsed in on itself, giant waves called tsunamis rose more than 40 meters (131 ft) high. These walls of water surged into 163 villages along the coastlines of Java and Sumatra, destroying them and killing almost 36,000 villagers. Floating islands of pumice endangered ships sailing in the Indian Ocean.

ß ON THE ERUPTION OF KRAKATAU IN MAY 1883, FOLLOWING WERE RECORDED

 1.       WEATHER CHANGES

Volcanic dust circled the globe for several years and lowered the Earth’s average temperature. Hawaiians noticed a white halo around the sun.

2.       IN TRINIDAD

In Trinidad, the sun appeared blue

3.       OVER ENGLAND

The evening sky over London dazzled onlookers with beautiful color-waves raised the tides in the English Channel.

4.       THE LOUDEST NOISE

The noise of the eruption was heard as far away as Madagascar.

5.       IN SRI LANKA

Observers have reported that the sun looked green in the first few weeks after the eruption.

6.       IN CALCUTTA

Giant waves destroyed riverboats in the Indian city.

7.       IN PERTH

The eruption caused a tsunami that destroyed this harbour in Australia.

8.       IN CENTRAL AUSTRALIA

To people living in central Australia, the blasts sounded like rifle shots.

 

 

 

 

 

 

 A picture of the most giant Volcano - Krakatau