Table 1 Volcanic Explosivity Index updated with umbrella cloud radius as an additional classification criterion.

From: The radius of the umbrella cloud helps characterize large explosive volcanic eruptions

Criteria | VEI

0

1

2

3

4

5

6

7

8

Volume of ejecta (m3)

<104

<106

<107

<108

<109

<1010

<1011

<1012

>1012

Column height (km)

<0.1

0–1

1–5

3–15

10–25

>25

–

–

–

Umbrella cloud radius (km)

–

<10b

<10b

<10

10–100

100–200

200–500

500–1000

>1000

  1. aAdapted from Newhall and Self47.
  2. bPlumes of transient eruptions will also develop gravitationally spreading clouds at the neutral buoyancy level, although of limited radii due to lower mass discharge rates.
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