May 18 – Mounting Concerns

Today’s Factismal: Mount St. Helens erupted 34 years ago today!

Thirty-four years ago today, Mount St Helens reminded us of just how powerful nature can be. Beginning at 8:32 AM, the eruption tore off most of the top of the mountain by noon and spread ash across fifteen states. The mountain shrank from 9,677 ft tall before the eruption to 8,363 ft tall after, removing nearly 4 billion cubic yards of rock in the largest landslide in recorded history. The blast cleared the forest for 17 miles from the northern side and spawned a mudflow that blocked the Columbia River shipping channel 70 miles away.

Amazingly, only 57 people were killed in the explosion. This was because scientists had been monitoring the volcano for years, recognizing that it was potentially active, not inactive. They had established a number of seismometers to measure the earthquakes associated with magma movement and has flown over the volcano several times to capture images of the incipient eruption and to put instruments into place to measure the tilting of the ground and its temperature (among other things). This information allowed them to predict when the volcano would erupt and to get most of the people to safety.

MtStHelens_IKO_2005068
1cascade_map

Though many people wonder when Mt St Helens will erupt again, vulcanologists are more interested in learning when the other volcanoes in the Cascades will erupt. There are over 100 volcanoes in Mt St Helens’ chain, stretching from California to British Columbia. All of them are caused by the subduction of the Juan de Fuca and Gordo plates under the North American plate; this is also what has created the Cascades mountains and the large number of large earthquakes in the region.

If you’d like to help scientists learn more about volcanoes and predict the next eruption, then why not join NetQuakes? You’ll keep a seismometer in your home and help monitor earthquakes and volcanic eruptions!
http://earthquake.usgs.gov/monitoring/netquakes/

One thought on “May 18 – Mounting Concerns

  1. Pingback: August 28 – Bardarbing, Bardarbang, Bardarbunga! | Little facts about science

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