A Year: Day to Day Men: 10th of April
In Cool Water
Mount Tambora’s eruptions reached a violent climax on April 10, 1815.
Mount Tambora is on the island of Sumbawa in Indonesia. It experienced several centuries of dormancy before 1815, caused by the gradual cooling of the hydrous magma in its closed magma chamber. During this cooling, crystallization of the magma occurred. resulting in an over-pressurization of the chamber and a rising of the temperature. In 1812, the volcano began to rumble and generated a dark cloud.
On the 5th of April in 1815, a very large eruption occurred, followed by thunderous detonation sounds heard in Makassar on Sulawesi 240 miles away, and as far as Ternate on the Molucca Islands 870 miles away. On the morning of April 6, volcanic ash began to fall in East Java with faint detonation sounds lasting until the 10th of April. Detonation sounds were heard on April 10th at Sumatra, more than 1,600 miles away.
At about 7 pm on April 10th, the eruptions intensified. Three columns of flame rose up and merged. The whole mountain was turned into a flowing mass of “liquid fire”. Pumice stones of up to 8 inches in diameter started to rain down around 8 pm, followed by ash at around 9–10 pm. Pyroclastic flows cascaded down the mountain to the sea on all sides of the peninsula, wiping out the village of Tambora. Loud explosions were heard until the next evening, April 11. The ash veil spread as far as West Java and South Sulawesi.
The explosion had an estimated Volcanic Explosivity Index of 7 (on a scale of 0 to 8) making it one of the most powerful in recorded history. An estimated 10 cubic miles of pyroclastic rock were ejected, weighting about 10 billion tons. This left a caldera measuring about four miles across and 2,300 feet deep. Before the explosion, Mount Tambora’s peak elevation was about 14,100 feet, making it one of the tallest peaks in the Indonesian archipelago. After the explosion, its peak elevation had dropped to 9,354 feet, about two thirds of its previous height.
The 1855 Zollinger report puts the number of direct deaths at 10,000, probably caused by pyroclastic flows. On Sumbawa island, 38,000 people starved to death; on Lombok island about 10,000 people died from disease and hunger. However, other journal reports put the combined deaths from volcanic activity and from post-eruption famine and epidemic diseases higher at 70,000 to 100,000 people. The ash from the eruption dispersed around the world, lowering global temperatures and triggering harvest failures.