Food For Thought by: Chita Dela Cruz-Heap

Volcanoes

The bulk of the Earth’s core is comprised of molten iron and nickel which is in a state of constant flux. The crust of the Earth is solid however, and is comprised of some fourteen tectonic plates which fit together like a giant jig saw puzzle.

The largest of these is the Pacific plate, the rim of which passes through California to the East, Alaska to the North, down through Japan and Indonesia to the West, and then Eastwards again across the Southern Pacific.

This fault line is known as ‘The Ring of Fire’, and it is along this fault line and others like it that most seismic activity occurs. Volcanic activity on the sea bed in some of the deepest parts of the ocean, where the Earth’s crust is thinnest is constantly creating new material, which in turn pushes the sea bed towards the perimeter of the Pacific plate.

Here at the perimeter the plate dips down under the adjoining plates, and as one plate slides over the other, friction between the two plates often creates earthquakes, or else releases molten magma in the form of volcanic eruptions

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The Earth has a long history of volcanic eruptions, with 1,500 active volcanoes around the world, 122 being active at any one time. These include: ‘strato’ Volcanoes such as Mt.St.Helens in Yellowstone Park, USA, which have steep sides and thick magma flows, and which are considered to be the most precarious; due to their steep sides, and the potential for land slips; ‘shield’ volcanoes which exhibit a much flatter profile; and ‘rift’ volcanoes such as those to be found in Iceland.

Mt. St.Helens has so far undergone three super eruptions, the first being 2.1 million years ago, the second 1.3 million years ago, and the third just 640,000 years ago. Scientist predict that the next eruption is now due, threatening to engulf Dallas, Kansas City, and Indianapolis.

Such a super eruption would see molten magma extruded at a speed of up to 700 mph, creating an ash cloud moving at 30 mph and covering some 4,000 square miles and settling on areas up to 500 miles away.

Other eruptions include that of Mt.Etna 8,000 years ago around 6,000 BC, which created a huge tsunami when 8 cubic miles of rock fell into the sea to cover 100 square miles of sea bed. The speed of the landslide was 200 mph, the speed of a Formula One racing car. A computer model of the event has established that the wall of water generated was 165 ft high and possessed the power equivalent to that of an atomic bomb.

Mt.Vesuvius erupted in Pompei in 79 AD. The temperature of the pyroclastic flow, comprising hot gasses and ash, measured over 1,000 degrees F. and travelled at a speed of 150 mph., burying most of the inhabitants of Pompei alive.

In 1815 Mt.Tambora in Indonesia erupted incinerating 10,000 of the local inhabitants. The cloud of ash emitted by the volcano circulated the world for several years, as a consequence of which some 80,000 people starved to death due to crop failure.

In 1883 Indonesia suffered again when Krakatoa erupted off the Indonesian coast. The resulting blast could be heard up to 2,000 miles away with this eruption too also generating a huge tsunami.

In 1991 it was the turn of Mt.Pinatubo in the Philippines, which was the largest eruption for eighty years. 75,000 people had to be evacuated from the area.

Despite the loss of life caused by the eruption of volcanoes, the biggest threat by far is that posed by crop failure. When Mt.Tambora erupted in 1815, temperatures around the world fell by 5 degrees and endured for several years.

When Mt. St.Helens erupts again as it surely will, the eruption is likely to be 20 times bigger than Tambora, and world temperatures could fall by as much as 25 degrees.

At no time in the history of man have volcanoes and the tsunamis that volcanic eruptions often cause posed as great a threat. There are many who believe that this is due to the rapid approach of the year 2012.

On December 21st 2012 all the planets in our solar system will form a straight line with the sun, an event which occurs only once in every 640,000 years. The precise effects of this coming alignment are uncertain, but it is more than likely that the Earth’s tectonic plates will be subjected to even greater pressure giving rise to increased seismic activity and creating the possibility of simultaneous earthquakes, eruptins, and tsunamis all around the world

Next week my column will deal with the subject of tsunamis, and the implications that they may have for us so don’t forget to pick up next issue of WVTE!/TE