When was Mount St. Helens' most powerful eruption?

Answer 1

The May 18, 1980 eruption of Mt. St. Helens was a Plinian style eruption with a volcanic cloud that exceeded 60,000 ft in height. The eruption was classified as a V.E.I. 5 from the United States Geological Survey. For further details on the style and proceeding events to the eruption please see Related Links Section.

Answer 2

this is how it erupt it was time that itv erupts os it took it about 12,00o years for it ti erupt and because it was cooled down for about 12,00 years and because magma has not be in it and for immediate action it about ot explode when for many reason it was a nature subtance so it erupt

Answer 3

The May 1980 eruption of Mt. St. Helens was specifically so explosive due to the amount of dissolved gasses that were present in the magma chamber. The volcano has an extensive history of explosive eruptions, and when fresh magma from depth enters the magma chamber, the magma mixing cycle will often times result in a very explosive eruption of the mountain.

Magma mixing will cause the issue within this volcano due to the fact that hotter magma from depth entering the magma chamber below Mt. St. Helens activates and triggers the gasses that have been dissolved in the cooler magma that has been there since the previous eruption to build pressures further than otherwise would happen. This will lead to often times a very explosive eruption due to the explosive discharge of the gasses.

Another issue with the eruption of 1980 was that it also accompanied a very large failure of the north flank of the volcano. This failure caused the north flank to slide down the mountain triggering the eruption within a very short time, as the pressure that had been holding the magma in place from above was now gone. This also caused what is known as a lateral blast effect, since gasses and fluids when under pressure will follow the path of least resistance on its way to the surface. In this case with the flank collapse to the north, the path of least resistance was through what was left of the north flank directing the explosive eruption due north from the volcano. This resulted in the blow down area that was so very well documented right after the eruption ended.

Answer 4

Mount St. Helens' most powerful eruption occurred on May 18, 1980. The eruption caused a massive debris avalanche and lateral blast, resulting in the devastation of the surrounding area and the loss of dozens of lives.

Answer 5

May 18th, 1980.