Eyjafjallajökull erupting on 27th March, 2010. We rate it as one of the worst eruptions in history.
Credit: Wikimedia
SYDNEY: “There is little that society can do in the face of the largest known volcanic eruptions, and it is a good thing that they happen very rarely on a human timescale,” says James White, volcanologist at the University of Otago in New Zealand. Scientists have improved capabilities for predicting some volcanic eruptions, but only if they know which mountains to monitor. Long-dormant volcanoes can awaken unexpectedly to wreak havoc.
NYIRAGONGO, DEMOCRATIC REPUBLIC OF CONGO 1977
Volume erupted: 0.01 km3 of lava
Killing mechanism: lava flow
Situated along the Great Rift Valley, Nyiragongo had a lava lake in its summit crater, which burst during the night in January 1977. Runny lava flowed down its steep sides at rates of nearly 100 km per hour, quickly draining the lake. More than 70 people died.
Nyiragongo erupted again in 2002, sending flows toward the city of Goma and the shores of Lake Kivu. Because of volcanism in the region, Lake Kivu accumulates carbon dioxide in its waters, and a major disturbance of the lake could result in a suffocating release of CO2.
7. MOUNT VESUVIUS, ITALY, 79 AD
Volume erupted: 3 km3
Killing mechanism: ash, pyroclastic flows
Vesuvius is considered one of the most dangerous volcanoes, as large populations lie in the path of potential eruptions. In 79 AD, an estimated 16,000 people in the Roman cities of Pompeii and Herculaneum were killed by pyroclastic flows – fast-moving, surface-hugging flows of ash, rock, dust and gas at temperatures of up to 700°C. Vesuvius has erupted about 50 times since 79 AD, with the most destructive in 1631, killing about 4,000 people.
6. LAKI FISSURE, ICELAND, 1783
Volume erupted: 12 km3 lava, 1 km3 tephra
Killing mechanism: atmospheric dimming, acid rain, crop die-off
One of the largest known historical lava flows occurred from the Laki Fissure, where rifting is tearing Iceland apart. A 25-kilometre-long fissure erupted 12 km3 of lava over the course of seven months. In this case, it isn’t the size that made it devastating but the environmental effects. Huge amounts of sulfur dioxide added to the atmosphere created acid rain, disrupted regional climate and left a lingering fog shrouding parts of the Northern Hemisphere.
The resulting famine killed tens of thousands across Western Europe, including up to a quarter of Iceland’s population. The recent eruption of Eyjafjallajökull is insignificant in comparison to Laki. Whereas the 1783 eruption sent 120 million tons of sulfur dioxide into the lower stratosphere, Eyjafjallajökull emitted only a fraction of that and it only reached the troposphere, where it is shorter-lived.
