Mt. St. Helens Anniversary

May 17, 2002


Provided by: Tim Martin, Greensboro Day School
Summary authors & editors: Tim Martin

May 18, 1980: 8:32 AM, a magnitude 5 earthquake shook the ground under an ever increasingly dangerous mountain. The earthquake started one of the largest landslides in recorded history causing the entire north flank of Mt. St. Helens to slide down towards the Toutle River valley. As the summit of the mountain slid away, pressure was released on the upward moving magma causing one of the most spectacular eruptions in United States’ history.

22 years later, the heart of the blast zone is still a barren landscape of volcanic blocks, bombs and ash. This image from the hummocks west of Harry’s Ridge was taken last June. From this vantage point, 4 miles due north of the caldera, one can easily see the lava dome that has formed from subsequent eruptions. The lava dome has grown to approximately 1000 ft above the caldera base and is over half of a mile wide. As the mountain continues to build, this dome may become the new summit of Mt. St. Helens.

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