Volcano!

Years ago my husband and I traveled to Washington State to visit our son and his family. One of the the most interesting things we did was a trip to the Johnson Ridge Observatory, located in the heart of the blast zone at Mount St. Helen's - the volcano. Many of you remember the last eruption there in 1980 that blew down or scorched  230 square miles of forest. Yikes. Anyway, we learned much and one thing in particular piqued my interest; a phenomenon known as "the silent zone."

It intrigued me to the extent that when I got home I wrote an article, geared towards children, and attempted to sell it. Never happened. But as I perused my files this morning I came across it again and thought it might interest you. Let me know. Oh - if you have kids or grand kids they might be interested, too.

An Eerie Silence

By Susan Sundwall

When you think of the eruption of a volcano, do you think – silence? Probably not. Most likely you’re thinking – BOOM! So imagine living near Mount. St. Helen’s in Washington State on the morning of May 18, 1980, when the volcano blew its stack. You watch the whole side of the mountain being torn away but you can’t hear a thing. It seems impossible, but a ten-year-old girl named Darcy Mitchem had it happen to her. At the time she lived with her family about twenty air miles from the volcano. “We saw the blast, but heard nothing,” she says. “It was like an eerie silent movie.”

There were many reports from other people who had the same experience. Hikers and climbers on Mount Adams as well as nearby Mount Hood and Mount Rainier also saw, but couldn’t hear, the astonishing volcanic eruption. When Mount St. Helen’s blew, the energy released was equal to ten million tons of dynamite. So why couldn’t some people hear it? It’s because Darcy and the people on those other mountains were in what scientists call the sixty-mile “silent zone.”

Way Up and Back Again

In order for you to hear a sound, sound waves must travel through the air and into your ear canal. The sound bumps against your eardrum signaling your brain that there’s a sound. The sound waves from the Mount St. Helen’s volcano blast rose so high and so fast that there was nothing for the waves to bounce off of until they reached the upper atmosphere. The atmosphere acted something like your eardrum, bouncing the sound waves back. But the objects they hit back on earth were sixty miles away from the center of the volcano. People many miles away heard the noise, but people in the silent zone couldn’t hear a thing. How weird is that?  

Recently

Since the day of the big eruption there has been other activity on the mountain. From October 2004 to late January 2008 there were four explosions blasting steam and ash up to 10,000 feet above the crater. This was scary, but not like the big explosion in 1980 when the eerie silent zone occurred.

Volcano Visiting

If your family is planning a trip to the Northwestern part of the country you can visit the Johnson Ridge Observatory to see and learn more about the volcano. Each year, over 10,000 students travel to Mount St. Helens and check out the dramatic effects of the 1980 eruption. You’ll also find out how local plants and animals have responded

I hope this has added a bit of obscure, but interesting, information to your carry-all this Monday. And thanks for reading!

Susan

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