1815 eruption of Mount Tambora

1815 eruption of Mount Tambora
False color image of Mount Tambora, taken from the Space Shuttle Endeavour on 13 May 1992 (for orientation, the top of the image is towards the East).
Volcano	Mount Tambora
Date	1815
Type	Vesuvian
Location	Sumbawa, Lesser Sunda Islands, Dutch East Indies 8°15′S 118°00′E / 8.25°S 118°E / -8.25; 118Coordinates: 8°15′S 118°00′E / 8.25°S 118°E / -8.25; 118
VEI	7
Impact	Reduced global temperatures, leading the following year, 1816, to be called the Year Without a Summer.

The 1815 eruption of Mount Tambora was one of the most powerful eruptions in recorded history and is the most recent known Volcanic Explosivity Index-7 event. The eruption of the volcano, on the island of Sumbawa in the Dutch East Indies (present-day Indonesia), reached a climax on 10 April 1815 and was followed by between six months and three years of increased steaming and small phreatic eruptions.

The ash from the eruption column dispersed around the world and lowered global temperatures, leading to worldwide harvest failures in an event sometimes known as the Year Without a Summer in 1816. The eruption resulted in a brief period of significant climate change that led to various cases of extreme weather. Several climate forcings coincided and interacted in a systematic manner that has not been observed since, despite other large eruptions that have occurred since the early Stone Age. Although the link between the post-eruption climate changes and the Tambora event has been established by various scientists, the understanding of the processes involved is incomplete.

Mount Tambora experienced several centuries of dormancy before 1815, as the result of the gradual cooling of hydrous magma in a closed magma chamber. Inside the chamber at depths between 1.5 and 4.5 km (0.93 and 2.80 mi), the exsolution of a high-pressure fluid magma formed during cooling and crystallisation of the magma. Overpressure of the chamber of about 4,000–5,000 bar (400–500 MPa; 58,000–73,000 psi) was generated, and the temperature ranged from 700 to 850 °C (1,300–1,600 °F). In 1812, the volcano began to rumble and generated a dark cloud.