Volcanic Explosivity Index (VEI)
|
Description |
Volume of Ejected Material |
Plume Height |
Eruption Type |
Duration |
Total Eruptions Given this VEI |
Example |
VEI |
Non- Explosive |
variable |
<100m |
Hawaiian |
variable |
699 |
Kilauea (1983 to present) |
0 |
Small |
<.001 km3 |
100- 1000m |
Hawaiian/ Strombolian |
<1 hr |
845 |
Nyiragongo (1982) |
1 |
Moderate |
.001-.01 km3 |
1-5km |
Strombolian/ Vulcanian |
1-6 hrs |
3477 |
Colima (1991) |
2 |
Moderate/ Large |
.01-.1 km3 |
3-15km |
Vulcanian/ Plinian |
1-12 hrs. |
869 |
Galeras (1924) |
3 |
Large |
.1-1 km3 |
10-25km |
Vulcanian/ Plinian |
1-12 hrs. |
278 |
Sakura-Jima (1914) |
4 |
Very Large |
1-10 km3 |
>25 km |
Plinian/ Ultra-Plinian |
6-12 hrs. |
84 |
Villarrica (1810) |
5 |
Very Large |
10-100 km3 |
>25 km |
Plinian/ Ultra-Plinian |
>12 hrs. |
39 |
Vesuvius (79 AD) |
6 |
Very Large |
100-1000 km3 |
>25 km |
Ultra-Plinian |
>12 hrs. |
4 |
Tambora (1812) |
7 |
Very Large |
>1,000 km3 |
>25 km |
Ultra-Plinian |
>12 hrs. |
0 |
Yellowstone Caldera (2 million years ago) |
8 |
Rate the Eruption
- Read the description below.
- Click on each category and select an entry that's closest to the
description.
- When you're ready to select a VEI number, scroll up to review the VEI
Chart above. Then select a VEI and click to see if you're right.
Eruption Observations
What began as a quiet morning suddenly took a violent turn. At 8:32 a.m. a
strong earthquake shook the Earth, triggering an avalanche and tearing the
volcano apart. The volcano's bulge and summit suddenly began to slide and
collapse, setting off powerful explosions. Rocks, ash, volcanic gas, and steam
were blasted outward. The blast flattened whole forests.
This lateral blast continued for two minutes and then stopped. Moments later
the volcano began to erupt upwards. An eruptive plume of ash rose more than
25 kilometers into the sky. Winds blew the ash eastward. Lightning, generated
by the swirling ash, set off forest fires. The Plinian eruption
continued until about 5 p.m. During that time, nearly 540 million tons of ash
fell over an area of over 57,000 square kilometers. The
total volume of uncompacted ash was about 1.25 cubic
kilometers—enough to fill a football field about 240 kilometers
high with fluffy ash.
Around noon, the volcano began giving off flows of pumice and ash, like a "pot
of oatmeal boiling over." These flows lasted for the next five hours. Mudflows
also started, sweeping down the volcano slopes, surging over hills, and causing
destruction to the areas below.
By early the next morning, most activity of this very large eruption ceased.
The sun rose to reveal a volcano that had changed in many ways—most
dramatically, it was 1,313 feet (400 meters) shorter than it had been the
morning before.