JavaScript Menu, DHTML Menu Powered By Milonic

Natural and Man Made Hazards



Volcanoes: Backgrounder

Emergency information

  • Volcanic ash can affect people hundreds of miles away from the cone of a volcano. Several of the deaths from the Mount St. Helens volcano in 1980 were attributed to inhalation of ash. Volcanic ash can contaminate water supplies, cause electrical storms, and collapse roofs.
  • An erupting volcano can also trigger tsunamis, flash floods, earthquakes, rockfalls, and mudflows.
  • Sideways directed volcanic explosions, known as "lateral blasts," can shoot large pieces of rock at very high speeds for several miles. These explosions can kill by impact, burial, or heat. They have been known to knock down entire forests. The majority of deaths attributed to the Mount St. Helens volcano were a result of lateral blast and tree blow-down.

Danger zones

Volcanic eruptions are most likely in the Pacific Rim states of Hawaii, Alaska, Washington, Oregon, and California. The chance of eruptions that could damage populated areas is the greatest for the active volcanoes of Hawaii and Alaska. Active volcanoes of the Cascade Mountain Range in California, Oregon, and Washington have created problems recently. The danger area around a volcano covers approximately a 20-mile radius. Some danger may exist 100 miles or more from a volcano, leaving Montana and Wyoming at risk.

What is a volcano?

A volcano is a mountain that opens downward to a reservoir of molten rock below the surface of the earth. Unlike most mountains, which are pushed up from below, volcanoes are built up by an accumulation of their own eruptive products lava, ashflows, and airborne ash and dust. When pressure from gases and the molten rock becomes strong enough to cause an explosion, eruptions occur. Gases and rock shoot up through the opening and spill over, or fill the air with lava fragments. Volcanic products are used as building or road-building materials, as abrasive and cleaning agents, and as raw materials for many chemical and industrial uses. Lava ash makes soil rich in mineral nutrients.

Help your community get ready

The media can raise awareness about volcanoes by providing important information to the community. Here are suggestions:

  • In a volcano prone area, publish a special section in your local newspaper with emergency information on volcanoes. Localize the information by including the phone numbers local emergency services offices, the American Red Cross, and hospitals.
  • Feature an interview with a representative of the U.S. Geological Survey, talking about how it determines the likelihood of a volcanic eruption.
  • Conduct a series on how to recognize the warning signals of a possible volcanic eruption.
  • Work with local emergency services and American Red Cross officials to prepare special reports for people with mobility impairments on what to do if an evacuation is ordered.

Did you know?

  • More than 80 percent of the Earth's surface above and below sea level is of volcanic origin. The seafloors and some mountains were formed by countless volcanic eruptions. Gaseous emissions from the volcanoes formed the Earth's oceans and atmosphere.
  • The May 18, 1980, eruption of Mount St. Helens in the Cascade Range of southwestern Washington occurred after more than a century of dormancy. The Mount St. Helens volcano took the lives of more than 58 people and caused property damage in excess of $1.2 billion.
  • The 1992 Mount Pinatubo eruption in the Philippines caused 342 deaths and an evacuation of over a quarter of a million people. An eruption of this size is likely to occur once every 200-400 years.
  • There are more than 500 active volcanoes in the world. More than half of these volcanoes are part of the "Ring of Fire," a region that encircles the Pacific Ocean.
  • The rock debris carried by a lateral blast at Mount St. Helens had an initial speed of more than 250 miles per hour. Fifteen miles from the volcano, the blast continued to move at a pace of approximately 60 miles per hour.
  • Crater Lake in Oregon formed from a high volcano that lost its top after a series of tremendous explosions approximately 6,600 years ago.

Outdoor Television »

Get the Flash Player to see this player.

More Outdoor Television