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The scale is open-ended with the largest eruptions in history given a magnitude of 8. A value of 0 is given for non-explosive eruptions, defined as less than 10,000 m 3 (350,000 cu ft) of tephra ejected; and 8 representing a supervolcanic eruption that can eject 1.0 × 10 12 m 3 (240 cubic miles) of tephra and have a cloud column height of over ...
On the Volcanic Explosivity Index scale, the eruption was rated a 5, and categorized as a Plinian eruption. The collapse of the northern flank of St. Helens mixed with ice, snow, and water to create lahars (volcanic mudflows). The lahars flowed many miles down the Toutle and Cowlitz Rivers, destroying bridges and lumber camps.
Volcanic eruptions that rated 6 on the volcanic explosivity index.Such eruptions release a tephra volume of at least 10 km 3 (2.4 cu mi) with profound long-term effects on the surrounding area and noticeable short-term effects on global climate.
A supervolcano is a volcano that has had an eruption with a volcanic explosivity index (VEI) of 8, [1] the largest recorded value on the index. This means the volume of deposits for such an eruption is greater than 1,000 cubic kilometers (240 cubic miles). [2] Location of Yellowstone hotspot over time.
As thermal expansion is a key factor in sea level variability, decreased heat content should result in a reduction in global mean sea level on a decadal time scale. [2] However, Grinsted [2007] argued that a significant sea level rise is the first direct response to the volcanic eruption, and after that sea level becomes to drop.
Volcanoes that have produced explosive VEI-7 eruptions.Such eruptions release a tephra volume of at least 100 km 3 (24 cu mi) with devastating long-term effects on the surrounding area and profound short-term effects on global climate.
While most volcanoes emit some mixture of the same few gasses, each volcano's emissions contain different ratios of those gasses. Water vapour (H 2 O) is the predominant gas molecule produced, closely followed by carbon dioxide (CO 2) and sulfur dioxide (SO 2), all of which can function as greenhouse gasses. A few unique volcanoes release more ...
The effect of major volcanic eruptions on sulfate aerosol concentrations and chemical reactions in the atmosphere. Major volcanic eruptions have an overwhelming effect on sulfate aerosol concentrations in the years when they occur: eruptions ranking 4 or greater on the Volcanic Explosivity Index inject SO 2 and water vapor directly into the stratosphere, where they react to create sulfate ...