Eruption of Mount Tambora 1815

Catastrophic Volcanic Explosion on Sumbawa Island in Indonesia

Feb 17, 2009

Noted to be one of the most powerful eruptions in historic times, Tambora caused tsunamis and days of darkness.

Indonesia is an archipelago located at the junction of four tectonic plates: Pacific, Eurasia, Philippine and Australian. With constant seismic and volcanic activity among the plates, this area is part of the Pacific Ring of Fire. Other notable volcanoes in Indonesia include Kelut in East Java, Merapi in Central Java, and Krakatoa in West Java.

Tambora was formed by an active subduction zone leaking magma into a chamber inside the mountain. Prior to the eruption in 1815, Tambora was a cone-shaped mountain which stood 14,000 feet high, making it one of the tallest peaks in Indonesia. After the 1815 eruption, a crater (caldera) was formed which is approximately 4 miles in diameter and 3,640 feet deep.

The 1815 Explosion of Tambora

Scientific experiments have indicated that Tambora had been dormant for 5,000 years but magma had been building up in the chamber. This build-up had reached its limit in 1815.

The first sign of activity took place in 1812 when small eruptions of ash and steam were accompanied by earthquakes. This continued until April 5th, 1815, when the first significant eruption took place. It sent an ash plume 15 miles into the air. This first eruption lasted approximately two hours.

The next explosion took place on April 10th, 1815 and this caused the collapse of the eruption column. As a result, pyroclastic flows down the slope wiped out the villages of Sanggar and Tambora. This eruption lasted approximately three hours. Columns of fire appeared at the top of Tombora.

From April 10th to April 15, 1815, volcanic activity continued with pyroclastic flows and ash fallout. The intensity of the blasts ranged from moderate to large.

On April 15th, 1815, the final and biggest blast occurred. Toxic gases, rocks, pumice and hot ash rushed across the island and instantly killed over 10,000 people in Tambora province. When this pyroclastic flow hit the water, it generated tsunamis to all the neighbouring islands which caused death and destruction. It is estimated that there were over 82,000 deaths resulting from the eruption of Mount Tambora.

According to National Public Radio; “Mount Tambora launched 100 cubic kilometers of rock into the air -- 10 times more than Italy's Vesuvius, which buried Pompeii in 79 A.D., and 150 times more than Mount St. Helens”.

The Aftermath of the 1815 Explosion of Tambora

The heavy fallout of ash blocked the sunlight for several days on the island of Sumbawa. The volcanic cloud from Tambora was carried to all parts of the world and lowered global temperatures by three degrees Celsius.

One year later, the cloud made its way to the northern hemisphere and caused cooler temperatures and crop failure. The year 1816 became known as ‘the year without a summer’. Many places had snow in June and frosty nights in July, August and September.

There have been several minor eruptions inside the caldera of Tambora which have produced small lava domes and flows. Although there has not been a catastrophic eruption since 1815, the mountain is continuously monitored by the Directorate of Vulcanology and Geological Hazard Mitigation, Indonesia.

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