On March 20, 1980, Mount St. Helens experienced a magnitude 4.2 earthquake; and on March 27, steam venting started. By the end of April, the north side of the mountain had started to bulge. On May 18, a second earthquake, of magnitude 5.1, triggered a massive collapse of the north face of the mountain. The magma in St. Helens burst forth into a large-scale flow that flattened vegetation and buildings over 230 square miles around.

Question

What geological impact did the 1980 eruption of Mt. St. Helen's (pictured below) have on the mountain and its surrounding environment. Select all that apply.

A.
Vegetation populations thrived.
B.
The summit height was reduced.
C.
Vegetation was flattened due to debris avalanche.
D.
The summit height was increased.
E.
The eruption has no geological impacts

Answer 1

The geological impact of the 1980 eruption of Mount St. Helens included the following:

B. The summit height was reduced.
C. Vegetation was flattened due to debris avalanche.

The eruption caused significant changes to the mountain's topography and devastated the surrounding environment, leading to the destruction of vegetation and alteration of the landscape. Thus, options A, D, and E are not correct.