Volcanoes And Some Historic Eruptions
Volcano - it conjures up vivid, lucid images of red-hot lava spewing out of a looming mountain, like mountain of fireworks gone astray, bruising and charring everything that dares to come in its way. But in reality there's so much more to learn about them.
According to geologists volcanoes are actually beneficial to humans living on or near them because they produce fertile soil, valuable minerals, water reservoirs, geothermal resources, and scenic beauty.
Volcanic eruptions can be placed into two general categories: those that are explosive, such as ones at Mount St. Helens, and those that are effusive, such as in Hawaii. The most active volcano in the world, Kilauea volcano on the island of Hawaii, is generally a non-explosive volcano and displays gently flowing lava, spatter cones, and lava fountains.
These non-explosive eruptions are the least dangerous type of volcanic eruptions since people rarely get killed by them. However, if you think it's a light and sound show, you're sadly mistaken as these eruptions come with their consequences.
Explosive eruptions produce fragmental rocks from erupting lava and surrounding rock. Some eruptions produce fine volcanic ash that rise many kilometres into the atmosphere.
Explosive activity causes widespread ash fall, pyroclastic flows and surges, debris avalanches, and landslides. Another mechanism for volcanic explosion is when surface water or ground water enters a magma chamber. These eruptions are likely when a volcano occurs in a wet area or in the sea.
In the past 500 years, over 200,000 people have lost their lives due to volcanic eruptions. An average of 845 people died each year between 1900 and 1986 from volcanic hazards.
Let's glance at the gory history of destruction that volcanoes have left in their wake and check the list of some the most destructive volcanoes.
Island of Thira, Aegean Sea
It was in the year 1640 BC when the population of the island of Thira in the Aegean Sea was rocked by a colossal volcanic eruption. It devastated the island, causing a large part of it to be submerged under the sea. Although no direct records of the eruption exist, it is inferred that it had a far-reaching effect on the Minoan civilization on nearby Crete and other islands.
Mount Vesuvius, Italy
It was a balmy August day in the year 79 AD, when the looming Mount Vesuvius generated a deadly mixture of hot ash, rock debris, and volcanic gases that wrecked the Roman cities of Pompeii, Herculaneum, and Stabiae in a matter of minutes.
The fact that a detailed report from the Roman official, Pliny the Younger, was found regarding the eruption and secondly, because the volcanic ash encapsulated the cities preserving them for modern-day study, has made this volcanic tragedy the most famous in the history of the globe. Virtually all aspects of Roman culture, including paintings, sculpture, architecture, and daily life by this eruption have been preserved. Mount Vesuvius is the only active volcano on the European mainland.
The largest lava-flow eruption on earth since the beginning of recorded history occurred in June 1783, when a fissure, 25 km in length, opened up in the southern highlands of Iceland and spewed out enormous
quantities of basalt lava for two months. Damaging gases were released, which contaminated the grasslands causing the loss of about 75 per cent of the livestock on the island and resulting in a 24 per cent loss of the Icelandic population.
On April 10, 1815, the Tambora volcano burst into life on the island of Sumbawa. The eruption ejected more than 100 cubic km of magma and a huge quantity of volcanic gases, killing a minimum of 10,000 people, thus making it the largest explosive eruption in recorded history. In addition, the fallen lava buried rice fields and other crops on nearby islands, leading to the deaths of more than 92,000 people from famine and disease.
On August 27, 1883, the island volcano of Krakatau in present-day Indonesia exploded violently. The eruption conjured up 100 tidal waves which struck the neighbouring islands of Sumatra and Java. Sweeping people out to sea, more than 34,000 people received a watery grave. Not just this, the hot pyroclastic surges from the eruption travelled more than 40 km across the surface of the sea and fatally burned at least 2,000 people. The explosion reduced the original island to small fragments and formed a volcanic crater.
Montagne Pelee, French West Indies
On May 8, 1902, the volcano Montagne Pelee on the Caribbean island of Martinique set off a relatively small explosion that sent pyroclastic flow and surges down its western flank. Although, it was a small eruption it became a heart-wrenching tragedy as the hot and swift-moving flow went directly into the highly populated city of Saint Pierre, then the capital of Martinique, killing nearly all 30,000 inhabitants.
Mount Saint Helens, United States
On May 18, 1980, the Cascade Range volcano of Mount Saint Helens in Washington state burst into life when an earthquake caused a landslide on the mountain's north face, taking off the top of the mountain. The eruption released about one cubic km of magma and spewed a cloud of ash and gases that reached as high as 19 kilometres.
A choking layer of ash spread over the nearby city of Portland, Oregon. Luckily, the 1980 eruption occurred in a largely unpopulated region, killing only 57 people. Mount Saint Helens had been dormant since 1857 but its sudden explosion awakened the American population to the numerous active volcanoes which exist in the United States.
Nevado Del Ruiz, Colombia
On November 13, 1985, the glacier-covered volcano Nevado del Ruiz in the Colombian Andes Mountains sent hot surges and pyroclastic flows across the glacier and snowfields, generating a great flood and mudflow.
The town of Armero which had the misfortune of being in it's path was struck in the night, burying the town and killing an estimated 23,000 people. Volcanologists had warned Colombian authorities that an eruption was imminent and Armero should be evacuated. If they had paid attention this catastrophe could have been averted.
Mount Pinatubo, The Philippines
Pinatubo had been dormant for 600 long years. It erupted on June 16, 1991. The volcano was active several times in June and July producing voluminous ash clouds and pyroclastic flows. Most severe, however, were the effects of mudflows after the main eruption. Heavy rainfall on the vegetation-free flanks of the volcano mobilized the loose volcanic ash and other material, creating deadly and destructive volcanic paths along the riverbeds and valleys. Although volcanologists had predicted the eruption, hundreds of people were killed.
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