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VOICE ONE:
This is Faith Lapidus.
VOICE TWO:
And this is Steve Ember withEXPLORATIONS in VOA Special English. On May eighteenth, nineteeneighty, a volcano exploded in the northwestern state of Washington.It killed fifty-seven people and destroyed huge areas of forest.Recently, that volcano has become active again. Today, we tell aboutthe famous Mount Saint Helens volcano.
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The Native American Indians in the state of Washington still callMount Saint Helens by its Indian name -- Loowit. It means "Lady ofFire." In the past two weeks, this famous "Lady of Fire" has beenwaking up after twenty-four years of sleep.
The last major explosion of Mount Saint Helens took place innineteen eighty. The volcano expelled fire, rock and volcanic gaswith a force of four hundred eighty kilometers an hour. Thatexplosion was three hundred fifty times more powerful than theexplosions of the first nuclear bombs.
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Recent earthquakes near MountSaint Helens were a sure sign that something was happening deepunder the ground. Scientists also knew there is a huge area ofmelted rock deep underneath the mountain. This liquid rock createspressure. The pressure can cause more earthquakes. When thousands ofsmall earthquakes began to happen, scientists knew Mount SaintHelens was becoming active once again.
Experts began to closely observe the huge volcano. They placedscientific instruments in many areas on the mountain. Theseobservations are still taking place twenty-four hours a day.
Scientists said the evidence showed a seventy percent chance thevolcano would do something. They were not sure exactly what it woulddo. But they were sure it would not be anything like the hugeexplosion in nineteen eighty.
VOICE ONE:
Volcano experts first observed increased underground activitynear the mountain on September twenty-third. The experts said thisactivity continued to increase. This evidence led the experts tobelieve it might produce a volcanic event.
Scientists observed more underground activity in the next fewdays. Then the volcano expelled steam and ash thousands of metersinto the air. Experts declared the volcano could once again be adanger. At first, they said the volcano was mostly a danger toaircraft. They said the ash could damage an aircraft's engines.
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The Mount Saint Helens area is a huge National Park. Thousands ofpeople visit each year to look at the large volcano and to learnabout the violent explosion in nineteen eighty. When there is nodanger, visitors can even ask for a permit to climb Mount SaintHelens. They can walk near the top and see down into the area calledthe crater.
The recent underground activity forced park officials to closethe visitor's center closest to the volcano. The Johnson RidgeObservatory is only eight kilometers from the mountain. Parkofficials told visitors to leave the area immediately.
The volcano expelled large amountsof steam for about thirty minutes on Monday, October fourth.Scientists said it was mostly water that had been super-heated bythe liquid rock far below.
The next day, however, the volcano once again began expellingsteam and ash several thousand meters into the air. Winds pushed thesteam and ash toward the northeast part of the state. When the ashcame down, it made driving a car difficult in some areas.
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Again, scientists said evidence gathered from the volcano showedmore explosions were possible. Experts also warned that explosionsof steam and ash were not the only concerns.
Extreme heat near the top of the volcano could melt the hugeformations of ice on the mountain. Some areas of ice are more thanone hundred eighty meters deep. Experts said extreme heat could meltthe ice and start huge floods and mudslides down the mountain.
By last Tuesday night, Mount Saint Helens had stopped mostactivity. Instruments that measured underground activity showed verylow levels. The earthquakes had almost stopped.
Tom Pierson is a scientist with the United States GeologicalSurvey. Mister Pierson said most evidence showed the possibility ofmore activity. However he says there is still a good chance thevolcano might go back to sleep. Other experts said all volcanoes gothrough periods of activity and rest. This could go on for days,weeks or even months. Officials lowered the threat level by the endof last week.
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By Monday, October eleventh, Mount Saint Helens was stillproducing steam. Cool weather made the steam look more threateningthan it was. Research teams were able to measure the heat from nearthe top of the volcano. The highest surface temperatures werebetween two hundred and three hundred degrees Celsius.
Experts say Mount Saint Helens could still explode if there werean increase in the amount of underground activity. They say theexplosion could take place suddenly or with very little warning.
Experts say it is extremely difficult to tell what a volcano willdo. For example, strong earthquakes and other underground activitynear the volcano produced good evidence. Earthquakes under MountSaint Helens were measured at about one each minute for long periodslast week. These were very small earthquakes. Most measured onlyabout one on the Richter scale.
But volcano experts cannot always tell what this evidence means.They cannot tell when an earthquake will grow stronger. And theycannot always tell what the hot liquid rock called magma is going todo. It is also difficult to measure the pressure created by themagma deep inside the volcano.
Most often scientists use all the information they can gather andtry to make a good guess. Above all, they try to provide the bestwarnings when they believe the volcano may become a threat.
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Around the world there are more than six hundred active volcanoes– those that have exploded within the past two hundred years. Thereare more than fifty active volcanoes in the United States. The mostactive ones are in the states of Alaska, Hawaii, California, Oregon,and Washington. There are twelve major volcanoes in an area ofmountains called the Cascade Range. These are in northernCalifornia, Oregon and Washington.
Volcanoes produce many different effects that can kill people anddestroy property. Extremely large explosions can threaten people andproperty hundreds of kilometers away. Volcanoes can also affect theweather on Earth.
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Mount Saint Helens is just one of a large number of volcanoesthat form a circle around the Pacific Ocean. This circle is calledthe Ring of Fire. Beginning in Japan, the ring of volcanoes extendssouth through the Philippines and Indonesia to New Zealand.
Across the Pacific, the ring begins again at the southern end ofSouth America and extends north along the Pacific Coast to Peru,Colombia, Mexico, and California. The ring stretches up the AmericanPacific Coast to Alaska and then across to the Kamchatka Peninsulaof Russia. The Ring of Fire includes about three-fourths of theworld's volcanoes.
Many of them have a tragic history of death and destruction. Forexample, in nineteen eighty-five, more than twenty-five thousandpeopled died as a result of the explosion of Mount Ruiz in Colombia.That volcano caused huge mudslides that covered many villages andtowns.
In Mexico, millions of tons of ash from El Chichon volcano killedmore than two thousand people in nineteen eighty-two.
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Recently, an earthquake in the central part of Californiameasured six on the Richter scale. Scientists say that earthquakeand volcanic activity at Mount Saint Helens are not linked. However,they say the two events have a common cause. The land mass deepunder the Pacific Ocean and the land mass of the Pacific coast aremoving toward each other. These land masses float on liquid rockdeep within the Earth.
This movement is called plate tectonics. It causes earthquakes.It also builds mountains and causes liquid rock deep in the earth toflow near the surface and form volcanoes.
As long as these huge land masses continue to move, people willcontinue to observe and study earthquakes. And they will studyvolcanoes like Loowit -- the Lady of Fire -- Mount Saint Helens.
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VOICE TWO:
This program was written by Paul Thompson. It was produced byMario Ritter. This is Steve Ember.
VOICE ONE:
And this is Faith Lapidus. Join us again next week forEXPLORATIONS in VOA Special English.