The Most Violent Volcanic Eruptions in Earth's History
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The most powerful volcanic eruptions in the history of Earth are the eruption on the volcanic island of Krakatoa, and the eruptions of the Tambora and Katmai volcanoes. These eruptions reached extraordinary force and were accompanied by enormous loss of human life.
What happened during the eruption on the volcanic island of Krakatoa?
The eruption that occurred on 7–9 September 1883 on the uninhabited volcanic island of Krakatoa ranks first by sheer destructive force. The island lies to the west of the entrance to the Sunda Strait, and the event produced the greatest explosion humankind has ever known.
Krakatoa, together with the nearby islets of Verlaten and Lang, was the remnant of an ancient volcano up to two kilometres high with a base 13 kilometres in diameter. A large part of the island — an area of about 75 square kilometres — was blown apart and scattered by the eruption. In its place ocean depths of up to 360 metres formed. The eruption began at noon on 7 September.
No direct eyewitnesses of the catastrophe survived, because the entire population of Sebesi Island, located almost 20 kilometres from Krakatoa, perished. Around one o'clock in the afternoon a menacing roar was heard in the city of Batavia (now Jakarta, the capital of Indonesia on the island of Java), situated 178 kilometres from Krakatoa. By night the noise had grown so strong that people could not sleep.
By the morning of the next day the sky cleared somewhat, but soon an impenetrable darkness fell that lasted 18 hours. Around 10 o'clock in the morning the eruption reached its greatest force. A column of ash rose, it is believed, to 30 kilometres. Clouds of ash covered ships at a considerable distance from the island. A violent storm broke out at sea — huge waves sank small vessels and threw them onto the shore.
The blast wave was felt especially strongly in Jakarta: in many houses not only did the windowpanes shatter and the lamps go out, but the window frames were pushed in and walls collapsed. The roar of the explosion was clearly heard not only in Australia, on the island of Ceylon and the Philippine Islands, but even on Rodrigues Island (part of the Mascarene group) — that is, at a distance of about 5,000 kilometres from Krakatoa.
In New York, 19,000 kilometres from the awakened volcano, fluctuations of the barometer were recorded in connection with the spread of the blast wave. The waters of the ocean were set in motion. A wave of extraordinary height — up to 36 metres — rolled across thousands of kilometres, washing away villages from the islands and destroying tens of thousands of people. About 36,000 people perished during this catastrophe on the islands of the Sunda Strait and along its shores.
On the coasts of Sumatra and Java vegetation was washed away in many places; uprooted trees and the corpses of people and animals lay about, and the ground was covered with mud and ash. Even on the island of Ceylon, about 3,000 kilometres from Krakatoa, the wave swept fishermen off the shoals. Having rounded the Cape of Good Hope, the wave reached the coasts of France and the British Isles and produced tides of unusual strength.
In an eastward direction the wave reached the shores of North America from Panama to Alaska. The masses ejected by the volcano consisted mainly of fine ash and pumice. On the islands nearest to Krakatoa a layer of these volcanic products up to 40 metres thick built up. The ash thrown out by the explosion spread over an enormous area, equal to roughly half of our country.
The total volume of volcanic ash was estimated by scientists at approximately 18 cubic kilometres. For a long time, especially in the winter of 1883 and the spring of 1884, the morning and evening twilights in Europe and America were exceptionally colourful.
The unusual colouring of the sun, the reddish ring around its disc and the fiery-purple glow of the dawn were explained by the presence in the atmosphere of finely divided ash particles raised to a height of up to 80 kilometres. An equally enormous quantity of pumice was ejected.
After the eruption, accumulations of pumice covered the surface of the ocean, and in places it formed standing floating islands rising 2 metres above the water. So much pumice gathered in the Sunda Strait that it hindered the movement of steamships. One Dutch warship ran into a pumice field and remained stuck there for six days, until the swell dispersed the accumulations of pumice.
In 1927, after forty-four years of dormancy, the almost vanished Krakatoa volcano resumed its activity: a new volcanic island, Anak Krakatau, arose on the site of the former crater.
How destructive was the eruption of the Tambora volcano?
The region of the Sunda Islands has more than once been the scene of terrible volcanic eruptions, and an exceptional place — by both force and death toll, more than 56,000 lives — belongs to the eruption of the Tambora volcano in 1815 on the island of Sumbawa (part of the Sunda group, east of Java). The eruption lasted several days.
When it reached its greatest force, impenetrable darkness held for three days around the volcano within a radius of more than 800 kilometres. The noise of the eruption was heard not only on the Greater and Lesser Sunda Islands, but even on the north-western coast of Australia — more than 1,000 kilometres from the volcano.
Most of the island of Sumbawa was covered with a thick layer of ash. Under its weight even stone buildings collapsed. A flourishing land turned into a grey, dead desert. On the island 12,000 people died directly. A further 44,000 perished under the ash and from famine, owing to the destruction of crops and animal fodder. Ash even reached Jakarta, 1,300 kilometres from the volcano, and the island of Celebes.
Pumice covered the ocean over enormous distances, obstructing the movement of ships. In addition, terrible disasters were caused by a hurricane that raged over the ocean when the eruption reached its greatest force. Waves of extraordinary height rushed onto the land and, although they raged for only three minutes, their effect was dreadful.
Forests and entire settlements were swept away; a whirling tornado tore trees up by the roots and seized individual buildings, animals and people. It is believed that the quantity of volcanic products ejected by Tambora was no less than 120 cubic kilometres — that is, roughly six and a half times more than Krakatoa ejected.
After the Tambora eruption, crimson-red sunsets were observed in Europe; moreover, the eruption's influence on the climate was noted, producing a marked drop in the average temperatures of the months, and of the year. According to contemporaries, it was the "year without a summer," a "disastrous year for farmers."
What made the eruption of the Katmai volcano remarkable?
Katmai, one of the volcanoes of Alaska, resembles Mont Pelée in the character of its eruption. An exceptionally powerful eruption of this volcano, lasting about two months, took place in the summer of 1912. As a result of several successive explosions, the summit of the volcanic cone was completely blown apart.
In its place, as later research established, a grim chasm formed almost 1,000 metres deep and about two kilometres across. It is believed that the volcano ejected about 20 cubic kilometres of solid eruptive products.
The area nearest to Katmai was buried under a layer of sand and ash up to three metres thick. While the ash rain fell, the surroundings of the volcano were plunged into impenetrable darkness for almost three days.
Everything in the immediate district of Katmai was changed beyond recognition: where dense, centuries-old forests had stood, a lifeless plain stretched out, and in many places streams of vapour and gas rose from beneath the layer of ash. This area is known as the "Valley of Ten Thousand Smokes."
Katmai lies in an unpopulated region, which is why its eruptions, as far as is known, occurred without significant loss of human life. You can explore the theme of the most powerful volcanic eruptions further by reading these articles:
- Iceland — the land of volcanoes and geysers;
- The eruption of Mount Vesuvius;
- A description of the volcanoes of our continent;
- Types of volcanoes and lava;
- The formation of volcanoes;
- The causes of volcanism.
