Before Mount St. Helens erupted, there was an earthquake with a magnitude of 5.1 that struck the north face of the mountain causing a massive landslide (largest debris avalanche on Earth in recorded history). That landside removed Mount St. Helens northern flank and part of the cryptodome that had grown inside the volcano. When Mount St. Helen erupted it could be heard for hundreds of miles away, removing 1,300ft off the top and scattered ash across a dozen states. The turbulently flowing hot rocks and gas quickly eroded, some ripping trees from their roots and destroying roads and bridges. …show more content…
Helens erupted in the Northern Hemisphere. It’s direct location is in Washington State, USA (continent is North America) (46.2º latitude north, 122.2º longitude west) on the plate boundaries between Juan de Fuca and the North American plates. The boundary is called ‘Ring of Fire’ which is a strand of volcanoes that congregate around the margin Pacific Ocean. On March 16th is when Mount St. Helens started showing signs of activity and along with that a series of small earthquakes. Eleven days later a few hundred more earthquakes and she finally erupted (small) for the first time in over a 100