Unzen, Japan
Elevation:1,359 m (4,457, feet)
Left: Mt Unzen, Japan.
In 1792, about a month after lava stopped erupting from the volcano, a landslide from nearby Mount Mayuyama swept through ancient Shimabara City, entered the sea, and generated a tsunami that struck nearby areas. More than 14,000 people were killed by the landslide and tsunami. The amphitheater-shaped scar of the landslide is still clearly visible on Mt Mayuyama just above the city.
Earthquakes occurred before and during the 1792 eruption, and a large earthquake after the eruption triggered a large-scale collapse of an old lava dome (Mayuyama; about 4 km (2.5 miles); dry avalanche and the resultant tsunami took 15,000 people's lives.
Mayon, Philippines
Elevation: 1,571 m (5,153 feet )
Left: Nue ardentes, like the ones in the above photo, were recorded
at 18 of these eruptions. Twelve eruptions have caused fatalities.
(Photo: Jim Moore, US Geological Survey, April, 1968)
Mayon Volcano lies in the eastern portion of the province of Albay and is about 300 km (186 miles) southeast of Manila. Well known for its beauty and near perfect cone, this active volcano is one of the tourist attractions of the country. Mayon reaches up to around 2,462 m (8077 feet) above sea level. Mayon is classified as a stratovolcano or composite cone.
The eruptions of Mayon are usually "Vulcanian" in nature or explosive. They are characterized by the mission of fine ash and ash-laden gases forming huge "cauliflower" clouds. The symmetry of the volcano indicates that the eruptions have always occured at the central vent and that these have never been violent enough to destroy Mayon's form.
Mayon, though sometimes destructive, is also productive. Its fertile slopes and surrounding plains, coupled by abundant rainfall through the year, have made Albay a rich agricultural region with the bulk of its population found in towns bordering the volcano such as Camalig, Gunibatan, Daraga, Legaspi, St Domingo, Ligao, Malilipot. The region is suited for growing abaca and coconut, two of Bicol's major crops, as well as palay vegetables.
The most recent eruption, in 1993, began unexpectedly with an explosion. The initial eruption lasted only 30 minutes but it generated pyroclastic flows that killed 68 people and prompted the evacuation of 60,000 others.
TopTambora, Indonesia
Elevation: 9,348 feet (2,850 m)
Left: Photo STS068-0263-0008 of Tambora from the Space Shuttle.
Tambora is a stratovolcano, forming the Sanggar peninsula of Sumbawa Island. The diameter of the volcano at sea-level is about 38 miles (60 km). Prior to the 1815 eruption the volcano may have been as tall as 13,000 feet (4,000 m). The 1815 eruption formed a caldera about 4 miles (6 km) in diameter. The caldera is 3,640 feet (1,110 m) deep.
The 1815 eruption of Tambora was the largest eruption in historic time. About 150 cubic kilometers of ash were erupted (about 150 times more than the 1980 eruption of Mount St. Helens). Ash fell as far as 800 miles (1,300 km) from the volcano. In central Java and Kalimantan, 550 miles (900 km) from the eruption, one centimeter of ash fell. The Volcanic Explosivity of the eruption was 7. The eruption column reached a height of about 28 miles (44 km). The collapse of the eruption column produced numerous pyroclastic flows. As these hot pyroclastic flows reached the ocean they caused additional explosions. During these explosion most of the fine-fraction of the ash was removed. The eruption formed a caldera. An estimated 92,000 people were killed by the eruption. About 10,000 direct deaths were caused by bomb impacts, tephra fall, and pyroclastic flows. An estimated 82,000 were killed indirectly by the eruption by starvation, disease, and hunger.
The 1815 eruption of Tambora caused the "Year without a Summer". Daily minimum temperatures were abnormally low in the northern hemisphere from late spring to early autumn. Famine was widespread because of crop failures.
Ruiz, Colombia
Elevation: 5,321 m (17,453 feet )
Left: Photo from U. S. Geological Survey.
Ruiz is the northern-most historically active volcano in South America. Because of the high elevation of the summit 5,321 m (17,453 feet, ), the volcano is capped by a large volume of snow and ice. In 1845 a summit eruption melted snow and ice and produced mudflows that traveled tens of miles from the volcano, killing 700 people. These mudflows were confined to the valleys that drain the volcano. The 1985 eruption of Ruiz, although only moderately explosive, produced mudflows which reached the town of Armero and killed more than 23,000 people. This eruption of Ruiz was the second mostly deadly of the century (Mount Pelee in Martinique was first, killing 29,000 people in its 1902 eruption). This photograph shows the volcano in the early stages of the 1985 eruption.
Armero, Colombia, destroyed by lahar on November 13, 1985. More than 25,000 people were killed in Armero when lahars (volcanic debris flows) swept down from the erupting Nevado del Ruiz volcano. When the volcano became restless in 1984, no team of volcanologists existed that could rush to the scene of such an emergency. However, less than a year later, the US Geological Survey organized a team and a portable volcano observatory that could be quickly dispatched to an awakening volcano anywhere in the world.
Cotopaxi, Ecuador
Elevation: 5,911m (19,388 feet)
Left: Photo by Pete Hall.
Cotopaxi (0.7S 78.4W) is a stratovolcano with a summit elevation of 19,388 feet (5,911 m). It has erupted 50 times since 1738. The 1877 eruption melted snow and ice on the summit, which produced mudflows that traveled 100 km (60 miles) from the volcano; more than 100 people died. The most recent eruption of Cotopaxi ended in 1904. Reports of an eruption in 1942 have not been confirmed.
Galunggung, Indonesia
Elevation: 2168 m (7111 feet)
Left: Photo by Jack Lockwood, U.S. Geological Survey, August 16, 1982.
Galunggung is a stratovolcano on the west side of the island of Java. The caldera of Galunggung is open to the southeast. The first historic eruption of Galunggung was in 1822. Since then the volcano has erupted four times most recently in 1984. Eruptions columns of Galunggung reached heights as great as 15 miles.
Two eruptions at Galunggung have caused fatalities. During the 1822 eruption, nuée ardentes and mudflows killed 4,011 people and destroyed 114 villages. The nuée ardentes extended up to 6 miles away from the volcano. During the 1982 eruption about 68 people died, mostly from indirect causes. Estimated damage was $15 million and 22 villages were left uninhabitable. The 1984 eruption was phreatic and lasted about two weeks. The April 1982- January 1983 eruption destroyed the 1918 lava dome and produced a new cinder cone in a new crater. The crater was about 2,000 feet across.
Volcano: Deadliest Eruptions