Agriculture
Flush-Free Fertilizer
Got Milk? How?
Vitamin D-licious Mushrooms
Amphibians
Salamanders and Newts
Poison Dart Frogs
Frogs and Toads
Animals
Hot Pepper, Hot Spider
A Wild Ferret Rise
New Elephant-Shrew
Behavior
The Electric Brain
Mosquito duets
The Science Fair Circuit
Birds
Ospreys
Pelicans
Songbirds
Chemistry and Materials
Screaming for Ice Cream
The Taste of Bubbles
The hottest soup in New York
Computers
The Earth-bound asteroid scientists saw coming
Music of the Future
Games with a Purpose
Dinosaurs and Fossils
A Rainforest Trapped in Amber
Fossil Forests
A Dino King's Ancestor
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Results of GSAT are in schools this week
Earth
Hot Summers, Wild Fires
Salty, Old and, Perhaps, a Sign of Early Life
Plastic-munching microbes
Environment
The Wolf and the Cow
Fishing for Fun Takes Toll
Plastic Meals for Seals
Finding the Past
A Long Trek to Asia
Oldest Writing in the New World
Watching deep-space fireworks
Fish
Great White Shark
Tilapia
Salmon
Food and Nutrition
Yummy bugs
A Taste for Cheese
Chocolate Rules
GSAT English Rules
Who vs. Whom
Pronouns
Who vs. That vs. Which
GSAT Exam Preparation Jamaica
Ministry of Education Announces 82 GSAT Scholarships for 2010
Preparing for the GSAT Exam
GSAT Practice Papers | GSAT Mathematics | Maths
GSAT Exams Jamaica Scholarships
GSAT Scholarship
GSAT stars reap scholarship glory
Access denied - Disabled boy aces GSAT
GSAT Mathematics
Math and our number sense: PassGSAT.com
Math is a real brain bender
Play for Science
Human Body
Sea Kids See Clearly Underwater
Kids now getting 'adult' disease
Heavy Sleep
Invertebrates
Dust Mites
Sea Urchin
Sea Anemones
Mammals
Whales
African Warthogs
Blue Bear
Parents
The Surprising Meaning and Benefits of Nursery Rhymes
Raise a Lifelong Reader by Reading Aloud
How children learn
Physics
IceCube Science
Electric Backpack
The Pressure of Scuba Diving
Plants
Farms sprout in cities
Plants Travel Wind Highways
Bright Blooms That Glow
Reptiles
Cobras
Crocodiles
Rattlesnakes
Space and Astronomy
Chaos Among the Planets
Sounds of Titan
Planning for Mars
Technology and Engineering
Roll-Up Computer Monitors to Go
Musclebots Take Some Steps
Weaving with Light
The Parts of Speech
Adjectives and Adverbs
What is a Preposition?
Countable and Uncountable Nouns
Transportation
Reach for the Sky
How to Fly Like a Bat
Middle school science adventures
Weather
A Dire Shortage of Water
Recipe for a Hurricane
Polar Ice Feels the Heat
Add your Article

A Volcano Wakes Up

After resting for nearly 2 decades, Mount St. Helens woke up this fall. Shaking ground and a skyward blast proved to the world that it’s still an active volcano.

Tiny earthquakes had been shaking the mountain for a week before it erupted on Oct. 1, 2004. The volcano spewed a gray plume of steam and ash 10,000 feet into the air. Hot magma began oozing out of the crater a few weeks later. As it kept coming, the magma literally built a small mountain in front of scientists’ eyes.

Mount St. Helens on a quiet day this fall, just before it spewed steam and ash into the air on Oct. 1, 2004.

Mount St. Helens on a quiet day this fall, just before it spewed steam and ash into the air on Oct. 1, 2004.

Forest Service, U.S. Department of Agriculture

These events weren’t as explosive as the massive eruption that blew the top off the mountain in 1980. But the recent activity at Mount St. Helens has kept scientists busy making observations and trying to guess what comes next.

“All of us geologists are curious to see what’s going to happen,” says Tom Pierson. He’s a research geologist with the U.S. Geological Survey.

Making a volcano

Mount St. Helens is in Washington State. It’s part of the Cascade Mountain Range, which stretches from British Columbia in Canada to northern California.

Mountains in the Cascades formed where two big chunks of Earth’s crust, called plates, ran into each other. When the plate under the Pacific Ocean pushed beneath the plate under North America, the incredibly high pressure and temperature caused rocks to melt into a gooey, superheated magma. The magma then seeped up through the crust. Occasionally, it reached the surface, creating volcanoes.

On the morning of May 18, 1980, Mount St. Helens demonstrated this ongoing process. The mountain erupted, sending ash more than 15 miles into the sky. The blast also went outwards, blowing out the north face of the mountain. This outburst caused massive landslides and leveled trees for miles. Lasting for 9 hours, the eruption killed fifty-seven people.

Mount St. Helens erupted on May 18, 1980, sending an enormous plume of ash into the sky.

Mount St. Helens erupted on May 18, 1980, sending an enormous plume of ash into the sky.

Austin Post, U.S. Geological Survey

Over the next 6 years, there were some small eruptions. At times, magma seeped out of the crater, creating a lava dome. Then, except for a few minor outbursts, all was pretty quiet on Mount St. Helens for about 18 years.

Puzzling earthquakes

When a swarm of small earthquakes started up in late September, it puzzled geologists. On Mount St. Helens, earthquakes usually mean that fresh magma filled with expanding gases is pushing toward the surface, shoving rocks aside.

Tom Pierson, geologist and volcano watcher, explains what's going on at Mount St. Helens to reporters.

Tom Pierson, geologist and volcano watcher, explains what’s going on at Mount St. Helens to reporters.

Kate Ramsayer

Scientists can detect these gases, including sulfur dioxide and carbon dioxide, using a special airplane that collects air samples. But when they made flights early this fall, the air didn’t have unusual amounts of the gases.

This would normally suggest that old magma was triggering the earthquakes. Like a flat soda, this magma would have already lost its gas, and the volcano probably wouldn’t erupt explosively.

But the earthquakes became more frequent and stronger as time went on. Altogether, they released more energy than had been released since the 1980 eruption. This didn’t fit with the old-magma hypothesis, Pierson says.

So geologists came up with a new hypothesis. Maybe fresh magma was causing the ruckus on Mount St. Helens. But airplanes couldn’t detect any released gas because it was being absorbed by the crater’s glacier.

Then seismographs, which record ground movements, detected something called a harmonic tremor. A harmonic tremor is a slow vibration of the ground. It’s a bit like the rattling sound you sometimes hear when water flows through pipes, Pierson says.

This ground motion told scientists that fresh magma was definitely on the move.

Seismographs record ground movements.

Seismographs record ground movements.

Kate Ramsayer

“Each one of these tremor events means the magma moved a little further,” says Jim Vallance. He’s a research geologist with the Cascades Volcano Observatory and the U.S. Geological Survey.

The increasing tremors and moving magma indicated that an eruption could occur within 24 hours of the first blast. On Oct. 2, scientists and park rangers with the U.S. Forest Service decided to move hundreds of volcano watchers back for safety.

“When you see a really strong tremor, it’s a good time to give the volcano a little room,” Bill Steele says. He’s the seismic laboratory coordinator at the Pacific Northwest Seismograph Network at the University of Washington.

However, nothing happened that weekend, showing that nobody can predict exactly what a volcano might do. Since then, the mountain has released several, small plumes of steam and ash.

A new dome

Many scientists are now excited about the creation of a new lava dome in the crater of Mount St. Helens. Since mid-October, magma has been breaking through the surface at a rate of about 7 or 8 cubic yards per second.

A new lava dome is forming in the crater of Mount St. Helens.

A new lava dome is forming in the crater of Mount St. Helens.

U.S. Geological Survey

“That’s like having a dump truck or cement mixer full of magma ejected every second onto the dome,” Steele says. “It’s pretty phenomenal.” Scientists can practically watch a mountain being built right before their eyes.

Will the dome continue to grow, or will the volcano take another rest? That’s the big question, says Willie Scott of the U.S. Geological Survey. There’s no reliable way for geologists to predict what a volcano will do.

“All we can do is monitor it closely and see if indeed it’s dying down or if it’s changing its behavior,” Scott says. “There’s no cookbook that tells us that, if we see this, this will happen.”

Scientists have several ways to keep an eye on the volcano. They can measure the gases that the volcano releases. These measurements give them clues about the magma beneath the surface.

They can use seismographs to track earthquakes, which have quieted down since the magma forged a path to the surface. Although the first eruption this fall destroyed some instruments, others have been slung into place on the crater by helicopter to measure the shaking.

Geologists can also look for changes in the shape and size of the mountain. They can look for hotspots on the crater by detecting the heat given off by the surface. They can collect rocks to study the magma itself.

Quick trips

Most of the monitoring equipment is placed in the crater by helicopter. A few times, however, scientists have made very quick trips to the crater floor to take samples or set up instruments. They don’t linger, though, because they don’t want to be there if the volcano erupts!

Still, scientists want to be able to detect any changes in the mountain that could signal danger. The new dome is unstable. If it collapses and clogs the magma flow, the pressure could build up and lead to an eruption. Ash in the air could cause problems for nearby airplanes. Mudslides or floodwaters from a melted glacier could harm people near the mountain.

“Any volcano surprises the people who are studying it,” Pierson says. It pays to pay attention.

A Volcano Wakes Up
A Volcano Wakes Up








Designed and Powered by HBJamaica.com™