What does the VEI index measure?
The Volcanic Explosivity Index (VEI) is a scale that describes the size of explosive volcanic eruptions based on magnitude and intensity.
What does VEI mean in volcanoes?
Volcanic Explosivity Index
Volcanic Explosivity Index (VEI) is a numeric scale that measures t… | U.S. Geological Survey.
What does VEI 7 mean?
Explosive volcanic eruptions occur in a wide range of sizes, and the modern world has not yet seen an eruption of either Volcanic Explosivity Index (VEI) 7 or 8, the highest 2 orders of magnitude known from written and geologic history (Newhall and Self, 1982; Mason et al., 2004; Global Volcanism Program, 2013).
What is the VEI scale and what is the criteria for a VEI ranking?
It measures how much volcanic material is ejected, the height of the material thrown into the atmosphere, and how long the eruptions last. The scale is logarithmic, or based on 10; therefore, an increase of “1” on the scale indicates an eruption 10 times more powerful than the number before it on the scale.
What is VEI and how does it work?
Volcanic Explosivity Index (VEI) is a numeric scale that measures the relative explosivity of historic eruptions. Volume of products, eruption cloud height, and qualitative observations (using terms ranging from “gentle” to “mega-colossal”) are used to determine the explosivity value.
Why is the VEI useful?
It is very valuable because it can be used for both recent eruptions that scientists have witnessed and historic eruptions that happened thousands to millions of years ago. The primary eruption characteristic used to determine the volcanic explosivity index is the volume of pyroclastic material ejected by the volcano.
What does VEI 0 mean?
A value of 0 is given for non-explosive eruptions, defined as less than 10,000 m3 (350,000 cu ft) of tephra ejected; and 8 representing a mega-colossal explosive eruption that can eject 1.0×1012 m3 (240 cubic miles) of tephra and have a cloud column height of over 20 km (66,000 ft).
What does VEI 3 mean?
VEI 2 eruptions produce between 0.001 and 0.01 cubic kilometers of ejecta. VEI 3 eruptions produce between 0.01 and 0.1 cubic kilometers of ejecta. With each step in the scale representing an explosivity increase of 10X, a VEI 5 is roughly ten times more explosive than a VEI 4.
What is the difference between a VEI of 1 compared to a VEI of 2?
Eruptions rated at VEI 1 produce between 0.0001 and 0.001 cubic kilometers of ejecta. Above VEI 1, the scale becomes logarithmic, meaning that each step in the scale represents a 10X increase in the amount of material ejected. VEI 2 eruptions produce between 0.001 and 0.01 cubic kilometers of ejecta.
What is the range VEI range?
0 to 8
Classification. With indices running from 0 to 8, the VEI associated with an eruption is dependent on how much volcanic material is thrown out, to what height, and how long the eruption lasts. The scale is logarithmic from VEI-2 and up; an increase of 1 index indicates an eruption that is 10 times as powerful.
What would a VEI 8 eruption be like?
Volcanic eruptions that rated 8 on the Volcanic Explosivity Index. Such eruptions release a tephra volume of at least 1,000 km3 (240 cu mi) with annihilating long-term effects on the surrounding area and devastating short-term effects on global climate, leaving profound effects on the climate for years to come.