- Mount St. Helens is a strato volcano, meaning it's built of layers of lava and ash. Strato volcanos are known for huge columns of ash when they erupt, unlike the splattering Hawaii volcanoes (which have a technical name that I can't remember).
- The column of ash from Mount St. Helens went 12 miles into the air.
- A bulge from a magma chamber formed on the side of the mountain before it erupted. A magnitude 5 earthquake caused a landslide that decapitated the chamber.
- Magma is melted rock and compressed gas. When the magma chamber was suddenly decapitated, it was like opening a shaken can of soda. The gases immediately expanded and that's what caused the eruption. The blast of hot air flattened forests for miles.
- Volcanic ash is pulverized rock. It's dangerous to airplanes because the heat from the engine melts the rock so it coats the inside of the engine.
- Mount St. Helens was expected to erupt vertically, but it erupted laterally. Because of this, at least one scientist was too close and died.
- Unlike other eruptions which built up the mountain, this eruption lowered the elevation.
Isn't that cool?
1 comment:
I remember coming home from church and me and my dad looking out the window and wondering why there was weird snow coming down. Then we realized it was ash. The whole town shut down for a week, we had to put pantyhose over the filters in the car, white surgical masks were a must for a week, and our veggies grew to be HUGE that fall because of all the ash in the soil. Oh, and shoveling the ash off the roof! Many memories...
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