Transcript
Volcanoes are places where Earth’s crust becomes weak. Then molten rock from below the surface (called magma) reaches the surface and becomes lava, which then cools and becomes rock. Over time, it will build up
to make a volcano.
Next, you should know what makes a volcano erupt.
Well, once the pressure of the magma located inside the volcano becomes too great for the volcano to handle, the volcano erupts so it can release the magma and the pressure.
. M o u n t S t H e le n s is a v o lc a n o lo c a t e d in
, S k a m a n ia C o u n t y.Wa s h in g t o n
Mount St. Helens is a stratovolcano, which is a tall, cone shaped volcano. It’s made of many layers (strata) of hardened lava, volcanic ash, and tephra.
Tephra is what volcano scientists (volcanologists) call the stuff that is blown out of a volcano during an eruption.
Th e e r u p t io n
o f M o u n t. S t H e le n s
w a s M a y18 t h ,
1 8 9 0 . Th e e r u p t io n
9 la s t e d.h o u r s
When Mount St. Helens blew, it was not just some lava flowing from the volcano. Instead, the morning of this huge natural disaster dawned bright and early with a magnitude 5.1 earthquake at 8:32am.
A month earlier, in April, the north side of the volcano was said to have a large bulge sticking out from it.
When the earthquake struck that morning, it started the sequence of events for the eruption.10 seconds into the eruption, the bulge and the rock around it started down the mountain in a giant rock avalanche.
As the avalanche crashed down the mountain, it got even bigger than it had started out. It rushed down the mountainside at 70 to 150 miles per hour. It destroyed everything in its path.
The force of the avalanche left a gap in the side of the mountain.
The gap was the escape for the pressure and magma that had been building up inside the volcano.
The bl ast f rom t he erupt i on sent hardened l ava (pumi ce) and ash i nt o t he ai r at speeds of 300 mph. I t was 660o F.
In just 10 minutes, the height of the ash reached 10 miles
into the air.
In just 10 minutes, the height of the ash
reached 10 miles into the air.
Mount St. Helens caused the death of 57 people,
the destruction of the woodland around it,
and killed many animals living on and around the mountain.
Mount St Helens is now 8,636 ft tall. That is 1,314 ft shorter than it was before the eruption
Mount St. Helens before and after the eruption
Scientists, photographers, campers, loggers, etc. were on the mountain the morning of the eruption. Nothing in the path of Mount St. Helens’ eruption was spared.
The car of Reid Blackburn, a photographer. He was one of the first victims of the volcano.
Fortunately, Mount St. Helens was able to be cleaned up with the efforts of people like Sarah Deatherage Koss. She made plans to clean up the aftermath of the eruption.
Rivers, lakes, and forests were destroyed by the blast of Mount St. Helens, as well as houses and roads. 25 years later, the area has made big improvements, but the people of Washington will never forget the eruption of Mount St. Helens.
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