[ v o l c a n o e s   :   c a s e   s t u d i e s ]


Click on the links to read about volcanic eruptions which have occurred throughout history.

Santorini (1470 BC)
The island of Santorini, in the Aegean Sea, exploded with more than a hundred times the strength of the most powerful hydrogen bomb ever tested by man.

Mount Etna (Catania), Sicily (396 BC)
One of Mount Etna’s earliest recorded eruptions, this event sent a 24-mile-long, 2-mile-wide lava flow that supposedly stopped the invading Carthaginian army.

Lipari, Sicily (126 BC)
Mount Etna, the largest volcano in Europe, erupted in 126 BC, plunging a mass of molten lava into the Ionian Sea. The waters were heated to boiling temperature, cooking thousands of fish. When the creatures were washed ashore, numerous citizens gorged themselves are were afflicted with a fatal "distemper".

Pompeii and Herculaneum, Italy (79 AD, August 24)
After a few short earthquakes, Mount Vesuvius exploded at 1 p.m., emitting a huge cloud of ash high into the atmosphere so thick that it made the day as dark as night. At first the people went about their normal routines, holding pillows or bark to protect their heads from falling debris. However, when the ash finally fell to earth, it buried the town of Pompeii, killing hundreds of its citizens. The volcano continued to spew ash, stones, and pumice for eight days. Thousands managed to escape, but others were suffocated beneath ash, mud, or steam and poisonous gases. Rain helped turn the ash to mud, which slid down the volcano’s slopes and buried the nearby town of Herculaneum in 20 feet of black ooze. Incidentally, Pliny the Younger, a Roman scholar whose records of the event mark the beginning of modern volcanology, claimed the column of ash looked like a towering pine tree, with a high, straight trunk and a horizontal spread of branches at the top. This type of eruption, now called Plinian, is commonly observed today. Pliny supposedly died from breathing poisonous volcano fumes, but it is more likely that he died from a heart attack. In 1699, almost 1600 years later, an Italian historian identified the buried area as the lost city of Pompeii, as described by Pliny the Younger. Researchers began to dig up the city on April 1, 1748, and they soon discovered murals and skeletons. The Herculaneum was uncovered quicker, when in 1710, and Austrian army officer found some marble in the dirt on his property. Archaeological digs continue at the site today, but the mud-lava nature of the earth is difficult to excavate.

Taupo, New Zealand (186)
Although details are sketchy, this explosion may have been the most powerful in history. The volcano blew away 80% of its own bulk, or 20 cubic kilometers, 220 kilometers into the air.

Pompeii, Italy (472)
Mt. Vesuvius erupted again. This time, some ash fell on Constantinople, 775 miles away.

Catania, Sicily (1169)
A major eruption of Mount Etna, accompanied by an earthquake, buried about 15,000 residents beneath collapsed buildings. The explosion was the worst recorded in twenty-three centuries.

Isle of Ischia, Italy (1301)
Volcano Epomeo erupted.

Pompeii, Italy (1583)
The famous Mt. Vesuvius erupted yet again, throwing out stones as large as cattle.

Pompeii, Italy (December 16, 1631)
Mt. Vesuvius erupted, unleashing seven flows of lava down the mountain that took six villages and 18,000 lives - its largest toll in history. The lava flowed 6 kilometers to the sea, where it formed a large peninsula. It sent ash clouds high into the air, causing thousands to flee for their lives. Mud flows also buried nine villages and 6,000 livestock.

Mount Etna (Catania), Sicily (1669, March 25)
A series of earthquakes destroyed nearby Nicolosi before one side of Mount Etna burst open with a roar that could be heard for fifty miles. The eruption sent a two-mile-wide flood of lava flowing over fifty villages and towns, eventually taking as many as 100,000 lives as well as starting a local war. Apparently, Catania had been preparing itself for an eruption by building a sixty-foot-high wall between the volcano and itself. As the lava approached, however, it became evident that the wall would not work. A crew of Catalians, led by Diego Pappalardo, then diverted the flow by cutting through the crust of cooled lava that formed a sort of levee along the edges of the flow. The newly freed stream fell away from Catania and headed straight by nearby Paterno. To defend their town, the citizens of Paterno took up swords and lances to drive the Catanians away from the gap they had created. As soon as the opening was closed, the lava continued toward Catania, where it poured over the wall and destroyed the city. Even today, some lava blocks Catania’s older streets.

Isle of Ischia, Italy (1762)
Epomeo erupted, killing thousands of people.

Papandayan, Java (1772, August 11-12)
The entire top of the 8,750-foot Mount Papandayan sank into a pool of lava, carrying with it forty villages and 3,000 people.

Mount Skaptar (Lakagigar), Iceland (1783, June-August)
Iceland, a 39,000-square mile island, owes its existence to volcanic activity. In fact, a major eruption occurs every six to seven years. The country’s most devastating blast occurred when the volcano, Laki, created a fifteen-mile-long fissure in the earth after a series of modest earthquakes rocked the island. Lava poured from the opening into the Skaftá River, overflowing the valley. For two more months, the lava crept forward on a front almost fifteen miles wide, filling a lake and two valleys. It spread over 200 square miles, destroying crops and burying 20 villages. The heat melted lots of ice, which then flooded the land. The steam it caused created rainstorms and more flooding. By the next spring, one-fifth of Iceland’s population and three-quarters of livestock had perished, taken by lava, flooding, famine, or poisoned by toxic vapors. The 12.3 cubic kilometers of lava emitted from the volcano is thought to be the largest lava flow in history.

Tambora, Sumbawa, Java (1815, April 5)
On the evening of April 5, 1815, residents on the island of Java heard something like cannon fire coming over the Java Sea. Over the next few days, ash fell from the sky while the ground continued to rumble. Travelers later cleared up the confusion - the mountain of Tambora had exploded on the island of Sumbawa, more than 750 miles way, creating the largest volcanic eruption since the Ice Age ended. 36 cubic miles of volcanic material were hurtled out of the cone, which had 4,000 feet of its own mountain face blown away. The explosion created a 7-mile-wide crater. The 13,000-foot volcano was long thought to be extinct, but had hidden for thousands of years under its lush surface a reservoir of magma. The pressure that had built up for so long was finally released, shaking the 2,500-mile Indonesian island chain in an explosion that killed 10,000 residents of Sumbawa and the surrounding islands. Huge seismic waves were created, and "whirlwinds sucked up men and animals". As many as 12,000 people perished in the initial blast, while more than 82,000 lives were taken subsequent famine and disease. The volcano also emitted about 170 billion tons of ash and debris in the atmosphere in a cloud so dense that it darkened islands 300 miles away for three days. A week later, dust showers fell 900 miles away. It also created a stratospheric haze that filtered sunlight around the world for years, an event that created amazing orange sunsets as far as England and deprived parts of Europe and North America of a summer.

Galunggung, Java (1822, October 8 and 12)
Two separate volcanic eruptions created steaming mudslides that poured into valleys, destroying 100 villages. 4,000 people perished in the initial blast. Four days later, another eruption destroyed the mountain summit and spewed rock and ash into the air.

Isle of Ischia, Italy (1881)
Thousands of people died when Epomeo erupted.

Isle of Ischia, Italy (1883, July 28)
The volcano Epomeo erupted, destroying 1,200 houses in the town of Casamicciola. There were over 2,000 casualties.

Krakatau, Indonesia (1883, August 26-27)
Tourists visiting the island in July of 1883 complained that the ground felt strangely warm. This was just one of the several signs that the island’s huge volcano was waking after two centuries of sleep. Dense clouds of steam and soot had been spewing out for several months, cloaking the islands in a smoky haze. By August, several ships were avoiding the island. Residents of Batavia, a nearby island, wrote how the city’s windows were cracking from underground vibrations. In the early dawn of August 27, huge explosions finally racked the island. The noise was so loud that it could be heard 4,800 kilometers (3,000 miles) away in Madagascar - the loudest noise recorded in history. Several billion tons of stone was thrown by steam 25 miles into the air, creating a hail of burning rock that killed hundreds. The volcanic eruption caused tsunami that circled the globe six and a half times and drowned more than 36,000. The waves reached heights of 175 feet, taking the town of Tetlok Betong, 50 miles away from Krakatau, and taking the lives of its 10,000 residents. More than 300 other villages and towns were ruined, many with entire populations swept into the ocean. The tsunami, racing at 400 miles per hour, hit the harbor at Calcutta nine hours after the explosion. In the opposite direction, the harbor at Perth, Australia, was also flooded. Sea waves caused by the blast were still recorded a week after the initial eruption. More than a year afterward, floating islands of pumice from Krakatau were discovered 7,500 miles away. In Batavia, 100 miles away, the sky turned as dark as night. Dust particles were carried 50 miles high into the stratosphere, where they were blown all over the world. For a full year after the event, only 87% of sunlight was able to shine through the particles in the atmosphere and reach earth. The reflection of light off these particles also produced amazing sunsets and sunrises. On October 30, citizens in Connecticut and New York (USA) rang fire alarms after seeing a bright red glow in the west. It was when scientists first discovered the relationship between the aerial shows and the volcanic eruption that they first had evidence of upper atmospheric air currents. Scientists a century later calculated that the blast had the force of 30,000 megatons, one million times greater than the atomic bomb that hit Hiroshima in WWII.

Tarawera, North Island, New Zealand (1886, July 10)
A volcanic eruption ruined Lake Rotomahana’s famous pink and white terraces, which had been formed from the deposition of calcium carbonate from hot springs. The lava from the eruption flowed into the lake and shattered the steps through a steam explosion.

Bandai, Japan (1888, July 15)
At 7:45 a.m., the Bandai volcano, which had been asleep for 1,000 years, blasted a 1.5-mile-diameter crater on its northern face. Large rock and earth chunks were sent high into the air, almost 4 miles above the volcano. Burning mud flowed down into valleys, taking almost 500 lives.

La Soufrière, Saint Vincent, West Indies (1902, May 7)
The Soufrière volcano, a large, shallow mountain with a crater lake, began to rumble in mid-February of 1902. The tremors began to grow in intensity, and finally an earthquake struck the island on May 6. The very next day, the volcano erupted, emitting a hot ash cloud up into the air that mixed with steam and gas, choking the citizens in the towns below. As many as 2,000 people perished from ash asphyxiation or burns, while others fled to the waters along the coast. Others found shelter in cellars. Within the next year, the volcano returned to normal, but it erupted again in 1979.

St. Pierre, Martinique (1902, May 8)
In April of that same year, the mountain by St. Pierre began to give off powdery ash that fell onto the city like gray snow. Residents were soon complaining of sore throats and trouble breathing. On May 5, boiling mud tore out of the volcano, carrying fifty-ton boulders and burying forty workers in a sugar mill alive. Despite all these warnings, the governor of the island insisted no danger existed. To prevent panic and evacuation, he sent 1,500 troops to keep residents from leaving. On May 8, a bright and clear day, the volcano blew apart. An eyewitness from a ship in the harbor wrote, "There was no warning. The side of the volcano was ripped out and there was hurled straight toward us a solid wall of flame. It sounded like a thousand cannons. The wave of fire was on us and over us like a flash of lightning. The town vanished before our eyes." The mountain blast apart on the side facing St. Pierre, flooding the city with a cloud of superheated gas. The intense heat, hotter than 1,000 degrees Fahrenheit, carbonized many objects. A single breath by a human meant death. After the cloud passed and the oxygen supply returned, the city erupted into flames. Out of a city of 30,000, only 2 men lived. Both men were terribly burned.

Mount Katmai (Valley of 10,000 Smokes), Alaska, USA (1912, June)
Katmai National Monument, a region of geysers and hot springs, was created in the largest volcanic eruption in North American history. In June of 1912, lava was suddenly drained from Mount Katmai, an event which produced an eruption of ash and debris that forced people to evacuate people 100 miles away in the city of Kodiak.

Mount Kelud, Indonesia (1919, May)
Mount Kelud’s crater lake became a boiling cauldron, sending hot water and lava pouring into villages below the mountain. 104 villages were destroyed and 5,000 people perished. This prompted Indonesian authorities to create a pipe system below the crater to drain away water.

Stromboli, Sicily (1930, September 11)
The Stromboli volcano, or "Lighthouse of the Mediterranean," got its nickname because it erupts every few minutes. The red lava is reflected by the hot streams of water vapor it emits, creating a fiery red glow.

Paricutín, Mexico (1943, February 20)
One day, a Mexican boy saw smoke rising up from a newly plowed field. Before long, hot ashes had pushed the earth away around a hole 80 feet long, spewing ash and hot rocks. By the same time next day, the ashes had grown into a mound as high as a house (35 feet). In a week, the mound had formed a hill about 150 meters (500 feet) high. One year later, the hill had become a cone-shaped mountain, 1,353 feet high, with hot ashes and lava pouring out of the crater at the top of the cone. The local people called the mountain Paricutín after the village it had swallowed up. The initial volcano eruption ejected enough ash to cover a 7-mile-radius area, killing a lot of plant-life. The ash also killed many predators of the cane borer, and insect that went on to destroy much of the sugar cane crop.

Mount Lamington, New Guinea (1951, January 15)
The 6,000-mile-high volcano had never before erupted in memory, but resurrected itself on January 15 when smoke appeared from the cone. Tremors shook the ground for two days, and the smoke became darker. On January 20, a huge cloud of ash exploded, sending cinders and dust showering down. An onrush of dust and steam rolled down the mountain, killing as many as 5,000 people and destroying many acres of cropland.

Mount Catarman (Hibokhibok), Philippines (1951, December 4)
Because no major eruption had occurred here since 1875, villagers were not too concerned about living near Mount Catarman. On December 4, however, the volcano erupted, sending lava and hot ash sweeping down the slopes. In minutes, 500 people had perished along with hundreds of animals, burnt and even mummified by the dehydrating gas clouds.

Myozin-syo, Japan (1952, September 24)
Myozin-maru-11, a fishing boat, reported seeing a newly created 150-meter long island 42 kilometers south of Tokyo. The volcanic island, created by an underwater cone, was gone within five days, even though submarine seismic activity continued. Two research ships went out to investigate, but as the Kaiyo-maru-5 sailed over a vent, the mountain erupted, killing 22 crew members and 7 scientists.

Mount Bezymianny, Kamchatka Peninsula, USSR (1956, March 20)
The largest single volcanic eruption in the twentieth century, according to some, occurred (thankfully) thirty miles away from the nearest human settlement. The eruption continued for a full year, from September 1955 to October 1956. The most destructive explosion, however, was at 5:11 p.m. on March 20, as shown by a recorded shock wave. A metalworker named Sorokin, who lived in Kamaki village 40 miles away, saw a huge jet of fire ejected from the mountain at a 30 degree angle, along with smoke and ash that filled the sky with darkness. The amount of ash ejected from Mount Bezymianny was enough to cover all of Paris 49 feet deep! The amount of energy needed to throw out 2.4 billion tons of debris is 40 trillion kilowatts.

Tristan da Cunha, south Atlantic (1961, October 9)
A tiny island of a few hundred people witnessed an eruption of a small volcano. The people were air evacuated to Great Britain.

Mount Agung, Bali (1963, January-May)
The 10,300-foot-high mountain destroyed a third of the island’s cropland, dislocating 85,000 villagers, and killing 1,500 people. The dust, scattered in the upper atmosphere, created amazing sunsets for weeks in the United States.

Taal, Philippines (1965, September 28)
An explosive vent sent incandescent bombs and cinders arcing over the volcano’s crater lake. As water soaked into the opening, a large steam explosion sent ash flying 12 miles high into the atmosphere, only to fall 50 miles away. Pumice was also shot out with so much force that trees half a mile away were pelted and stripped of their bark. Lava killed at least 350 citizens.

Mount Mayon, Philippines (1968, April 20)
8,000-foot-high Mount Mayon sent steam and lava exploding out of its cone. 3,000-foot-high fire balls were also sent hurtling out, prompting the government to evacuate 70,000 people within a 6-mile-diameter area. Because of this, there were no casualties.

Mount Arenal, Costa Rica (1968, July 29-August 1)
Mount Arenal has erupted frequently, making it one of the most active North American volcanoes. 80 people were killed by nuée ardente, and lava covered many houses and fields.

Helgafell, island of Heimaey, Iceland (1973, January 23)
After 7,000 years of dormancy, the Helgafell volcano erupted in the early morning while most nearby residents were still sleeping. A 1.6-kilometer crack appeared on the slope, out of which poured lava and ash. Eventually, the fissure opened all the way to the ocean, allowing lava to flow into the water. Giant steam clouds enveloped the harbor while lava fountains shot up as high as 375 feet. Cinder and ash rained down, burying roads and buildings. The village’s fishing boats and ships were used to evacuate 5,500 people to the mainland without any lost lives. The volcano continued to erupt until July. 3 square miles of land were covered by lava up to 200 feet deep. In addition, a new, 600-foot-high volcanic cone, named Kirkjufell (“Church Hill”), was born along the fissure. After villagers returned, they used Helgafell as an energy source.

Mount Baker, Cascade Mountains, Washington, USA (1975, March)
10,778-foot-high Mount Baker began to send out sulfurous gases through fumaroles (blowholes), causing nearby residents to believe a forest fire had began along the peak. The U.S. Forest Service closed down a recreational area on the slopes. Although the volcano did not erupt, a scientific research team that investigated the activity believed it could signal an oncoming volcanic event.

Kamchatka Peninsula, USSR (1975, July)
A new 1,000-foot-high volcano was born in six weeks. The mountain sent out 10,000-foot-high ash and gas clouds, as well as 3,000-foot-high lava bombs.

Nyiragongo, Zaire (1977, January 10)
70 people perished when fast-flowing lava caught them in an eruption at the Nyiragongo Crater, a pool of red-hot lava that sent up smoke clouds. On January 10, the bubbling lava, which is usually contained within the crater, seeped out through fractures along the mountain slopes, spilling down the sides in less than an hour.

Mount Sinila, Java, Indonesia (1979, February 20)
Poisonous gases caused the deaths of over 175 people.

La Soufrière, Saint Vincent, West Indies (1979, April)
10,000 people were forced to evacuate when Soufrière erupted, but little damage was done to the island.

Mount Merapi, West Sumatra, Indonesia (1979, April 30)
Stones and lava poured down on several nearby villages, taking 149 lives. Mud slides buried 30 residents.

Mount Etna, Sicily (1979, September 12)
Mount Etna suddenly erupted, sending lava and rocks onto a hiking trail where a tour group was walking. Six people were killed and another 40 injured by the unexpected event.

Mount St. Helens, Montana, USA (1980, May 18)
Mount St. Helens had been dormant for 123 years when it suddenly erupted at 8:32 a.m. Ash-filled steam and gas blasted out horizontally from the mountain at up to 670 miles per hour, snapping off six million trees and scattering them like toothpicks over a 130,000-acre area. The event occurred in near silence. Muted by the ash, dust, and fir needles in the air, the sound waves only carried thirty feet. The explosion of the volcano was as large as 500 small atomic bombs, but luckily there were very few deaths. The death toll was 34, with 27 others missing. 10,000 animals are estimated to have been killed, along with 15,000 acres of destroyed forestland. Damage was estimated to exceed $800 million.

Colombia (1985, November 20)
Nevado del Ruiz, a long-dormant volcano in this South American country, killed about 22,500 people, not by emitting steam, ash, or lava, but by suffocating residents in a sea of thick mud. Two explosions thrust millions of tons of ash into the air. Ramón Antonio Rodrigues, the mayor of the town of Armero, was describing the event over the ham radio to friend in Ibaque when he suddenly cried, “Wait a minute! I think the town is getting flooded.” The radio then went dead. At that moment, the community was drowned in a mile-wide river of cold goo. Most of the people were trapped and killed, while 80% of the buildings were buried. Thousands of people were instantly buried beneath up to fifteen feet of slime. The torrent then warmed and became a steaming river up to fifty feet deep, repeating its destruction in other nearby communities. Rescuers continued to excavate trapped survivors, many of whom were unable to cry for help because their mouths were full of mud. Actually, the volcano had been occasionally sending up plums of smoke for more than a year. A government agency had forewarned of the disaster, but too much time was taken in response to the predictions.

[ back to graphics version ]

Forces of Nature: ThinkQuest 2000 (Team #C003603)

http://library.thinkquest.org/C003603/english/volcanoes/casestudies.shtml