The Indonesian Merapi volcano seems to be ready to blow in a big way. This should make the global warming people extremely happy as the volcano contains 3 times the amount of magma that the Tambora eruption contained, which lowered temps around the globe. Nature always seems to find a way to balance things out, doesn’t it?

The year without a summer

“the bright sun was extinguish’d… morn came and went–and came, and brought no day”
Darkness by George Gordon, Lord Byron

Photo courtesy of the Smithsonian Institution, taken by Rizal Dasoeki, 1986 (Volcanological Survey of Indonesia)


On April 10, 1815, for the first time in about 5000 years, Tambora erupted. A series of large explosions began, sending a massive volcanic column into the air. This eruption was the biggest eruption in recorded history.


Tambora is a stratovolcano located on the island of Sumbawa in Indonesia (see map below), forming the Sanggar peninsula of the island. The island is part of a very active volcanic arc, which is part of the Ring of Fire around the Pacific Ocean.

Map Courtesy of United States Geological Survey. Public Domain.

The Build-up

Before the explosion, Tambora stood over 4000 m (13000 ft) high. Starting in 1812, 3 years before the huge eruption, the volcano started spewing steam and ash, and creating small tremors in the Earth. What people didn’t know is what was coming next…

On the 5th of April, 1815, after laying quiet for over 5000 years, the first eruption began, lofting a volcanic column 25 km (15.5 miles) into the sky. This initial eruption was heard over 1000 km away.

The Eruption

On April 10, 1815, a series of eruptions began, culminating to the largest eruption in recorded history. The eruption lasted several days. It blew a chunk off of the mountain almost a mile wide. The volcanic column, after flying 40 km into the sky, returned to the ground, creating a huge pyroclastic flow of ash, pumice, and debris. The pyroclastic flow alone killed more than 10,000 people in its path. The ash that fell from Tambora travelled as far as 1300 km (800 miles) away.

When the pyroclastic flow reached the ocean, the debris created such a large displacement of water that tsunamis as high as 5 meters emanated out from the island. These tsunamis caused flooding, devastation, and death on many of the other Indonesian islands.

After the eruption was over, and estimated 100-150 cubic kilometers of ash and debris were said to have been ejected from the mountain. [for reference, in 1980, Mt. St. Helens ejected about one or two cubic kilometers]- see graph below

Copyright 2004, W. W. Norton. Used by Permission

Volcanoes are measured by a Volcano Explosivity Index (VEI), on a scale of 1-8. Tambora had a VEI of 7. Only 4 other volcanoes in the last 10,000 years have had a VEI that high, and Tambora is the only volcano in recorded history with a VEI of 7.

Satellite photo: NASA Public Domain

The Aftermath

The giant crater left at the top of the volcano (aka caldera-see image above) 4 miles wide and 3,640 ft. deep, a hole that is still quite obvious today. The ash that fell from the eruption at Tambora was devastating, killing all the crops and vegetation, causing more than 80,000 more deaths from famine and disease. This death count is the largest from any volcano eruption in recorded history. In addition, the amount of sulfur dioxide that was released into the stratosphere made 1816 the year without a summer.

The Year without a Summer

In 1816, the overal temperature on Earth, specifically in the Northern Hemisphere, lowered so drastically that it became known as the year without a summer. Weather was disturbed all over, with problems in Western Europe and the United States, as well as Asia. Monsoon season was affected, which is thought to also be tied to a cholera epidemic that year. In places like New England and Canada, frost was recorded in every month of the year, and snow fell in June. This phenomenon is known as global cooling.

The summer temperatures in 1816 averaged just a few degrees below normal, but as mentioned, it frosted throughout the summer. The highs were still close to 100 degreed Fahrenheit on some days. However, the cold spells, especially at night, cause massive crop failure, and, as a result, even more famine.

200 million tons of sulfur dioxide was shot up into the stratosphere. The sulfur dioxide prevented much sunlight from reaching the Earth’s surface, lowering the overall temperature, and killing crops and many creatures as a result. This crop failure caused mass famine, which was what caused the death toll to be so high.

The global changes in temperature did not occur until a year later. This delay was due to the fact that the stratospheric winds take that long to distribute the sulfur dioxide and volcanic ash all around the world.

The Response
During the year with no summer, many artists all over the world felt moved to write about it. Among those people were Mary Shelley, Lord Byron, and William Turner (see painting below). Mary Shelley wrote the very well-known book entitled Frankenstein to help portray the dismal feeling of 1816. Lord Byron wrote the poem Darkness in response to the weather.

“The Slave Ship” 1840 by William Turner. Public Domain

Literature Cited

Furgang, Kathy. Tambora: a Killer Volcano from Indonesia. The Rosen Publishing Group, Inc.: New York. 2001.

Gordon, George. “Darkness” as found at Accessed on April 9, 2005.

Marshak, Stephen. Essentials of Geology. W. W. Norton & Company: New York. 2004.

NASA. 2002. Volcanoes and global cooling. Accessed April 11, 2005.

Oppenheimer, C. 2003. Climactic, environmental, and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815. Progress in Physical Geography 27:2. GeoREF. Accessed April 11, 2005.

San Diego State University Geology Department. date unknown. Climate effects of volcanic eruptions. Accessed March 15, 2005.

Smithsonian Institution. date unknown. Tambora. Accessed March 15, 2005.

Suri, Dan. 2002. 1816-The year without a summer. Accessed March 15, 2005

Taylor, David. 2004. The year without a summer. Accessed April 9, 2005.

University of North Dakota-Volcano World. 2005. Tambora, Sumbawa, Indonesia. Accessed March 15, 2005.

Author: Becca Ethridge
Creation/revision date: December 8, 2007