Keeping "volcano mania" in perspective -- Science Feature
Movie buffs, who will be bombarded by a series of big-screen and "made for TV" movies about volcanoes during the next few months, may wonder what is being done to reduce the risk of a real-world disaster the next time an eruption threatens local communities or the skies above.
"Plenty," say USGS volcanologists who have worked at some of the world’s most dangerous volcanoes. "Volcanic eruptions have tremendous potential for destruction, but we are learning how to reduce the risk through research, planning, and public education," said Robert Tilling, chief of the USGS Volcano Hazards Team in Menlo Park, Calif. Starting at Mount St. Helens in 1980 and continuing to the present day, USGS scientists have responded to dozens of volcano crises in the United States and elsewhere. By assessing hazards from future eruptions based on a volcano’s past behavior, carefully monitoring for signs of restlessness, and keeping public officials informed of the dangers, scientists have helped to save thousands of lives and millions of dollars worth of property throughout the world.
"Enjoy the movies," Tilling said, "but remember that natural processes like volcanic eruptions only turn into natural disasters when humans get in the way. We can live in harmony with our active volcanoes, but only if we respect their power and plan accordingly."
"Not all hazards from eruptions are limited to the immediate vicinity of the volcano," said Dan Dzurisin, scientist-in-charge at the USGS Cascades Volcano Observatory (CVO) in Vancouver, Wash. "Huge debris avalanches and associated volcanic mudflows, such as those at Mount St. Helens in 1980, can travel tens of miles down valleys surrounding a volcano. In some cases, it may be safer to be closer to an erupting volcano and on high ground than it is to be farther away and on the floor of a valley."
Even more far-reaching than avalanches and mudflows are plumes of volcanic ash, shot high into the atmosphere, that could damage or even bring down an airliner hundreds of miles from an erupting volcano. This has become a serious problem in recent years as air traffic through some of the world’s worst "volcano shooting galleries" has increased dramatically. "A prime example is our own Aleutian volcanic chain in Alaska," said Terry Keith, scientist-in-charge at the Alaska Volcano Observatory (AVO), a facility jointly operated by the USGS, Fairbanks Geophysical Institute of the University of Alaska, and Alaska Division of Geological and Geophysical Surveys. Every day, dozens of planes fly over or near some of the Aleutian’s most active volcanoes. In 1989, a Boeing 747-400 aircraft descended into what appeared to be a thin haze layer while on approach to Anchorage International Airport. In fact, the "haze" was volcanic ash from a small eruption of nearby Redoubt volcano. The jumbo jet lost power from all four engines for several agonizing minutes before the crew was able to restart them and land safely. Although no one was injured, damage to the plane was approximately $80 million. To avoid such costly and potentially deadly encounters in the future, the USGS, Federal Aviation Administration, and National Weather Service are working with similar agencies around the world to provide timely warnings of dangerous ash plumes. "Last year, we installed monitoring equipment on four additional volcanoes in the Aleutians, and this year we’ll start monitoring four more," said Keith.
Hazards from an erupting volcano can take many forms, including blasts, debris avalanches and debris flows, pyroclastic flows, lava flows, ashfall and poisonous gases. "By studying a volcano’s eruptive history, we can get a pretty good idea of which hazards pose the greatest risks," according to USGS researcher Kevin Scott. "At Mount Rainier, for example, we know that debris flows have repeatedly buried all of the valleys surrounding the volcano during the past few thousand years, and they will continue to do so in the future." In recent years, USGS scientists have focused their attention on the volcano’s history of debris flows and on mapping its ice-covered cone. Scott noted that an important difference between the last giant debris flow that swept down Mount Rainier’s western slopes about 500 years ago and the one that could happen in the near future is the large number of people who now would be at risk.
Some of the most dramatic scenes of volcanic eruptions and those that most often come to the minds of Americans are the spurting lava fountains and red-hot lava streams of Hawaii. Although they are spectacular and destroy everything in their path, few lives are lost to these types of eruptions, because there is usually time for people to safely evacuate when threatened by an advancing flow. On the Island of Hawaii, in fact, where Kilauea volcano has been erupting almost continuously since 1983, the eruption has destroyed more than 185 residences and other structures for a loss of $ 61 million, yet only one person has lost his life. "Deadly explosive eruptions can occur in Hawaii, but they are infrequent, said Don Swanson, scientist-in-charge at the USGS Hawaiian Volcano Observatory (HVO). "We take advantage of the volcano’s frequent but usually safe eruptions to learn as much as we can about how volcanoes work, so we can apply what we learn to other, less friendly and less-cooperative volcanoes. But we also have some unique volcano-related health hazards to deal with here. Lava flowing into the ocean triggers a chemical reaction that produces a noxious brew known as "vog" or volcanic smog. Medical researchers have documented deleterious human health effects of exposure to vog and other volcanic gas, and we volcanologists have recognized the need to work with chemists and meteorologists to better understand the phenomenon."
USGS volcanologists also are keeping a close eye on other potentially active volcanic systems, including Yellowstone caldera in Wyoming and the Long Valley-Inyo-Mono volcanic chain at the base of the Sierra Nevada of eastern California. Just one week after the devastating eruption of Mount St. Helens on May 18, 1980, the Long Valley area was rocked by four magnitude-6 earthquakes within 48 hours and thousands of smaller ones over the next several weeks. Since then, Long Valley has been one of the more restless volcanic systems in the world. David Hill, USGS scientist-in-charge for Long Valley, explained, "Since 1980, an area near the town of Mammoth Lakes has experienced thousands of small earthquakes, uplift of the ground by as much as two feet, and increased fumarolic activity." A swarm of earthquakes beneath Mammoth Mountain in 1989 accompanied an intrusion of magma beneath the volcano that failed to make it to the surface, but got close enough for carbon dioxide gas released from the magma to kill trees in the area.
So, with all the media hype focused on erupting volcanoes, what are the odds that an eruption will occur anytime soon? In Hawaii, there’s no clear end in sight to the eruption that started in 1983-it might continue for years or even decades.
The remote volcanoes of the Aleutian chain in Alaska typically produce two or more eruptions every year, posing a significant threat to aviation safety.
The Cascade volcanoes of Washington, Oregon, and northern California produce an average of one to two eruptions per century, but here the risk is larger owing to the greater population density.
For most of the volcanoes in the conterminous western United States, we’ve identified the areas likely to be threatened by future eruptions on hazard-zonation maps, which provide a basis for long-range planning. The best way to minimize the effects of an eruption, after all, is to incorporate hazards information in land-use planning to avoid high-density development in hazardous volcanic areas.
The USGS volcanologists’ best advice is to enjoy the season’s volcano movies for their entertainment value, but keep in mind that real eruptions are serious business. By staying informed, you can significantly reduce your risk from future eruptions. If you think your community could be threatened by a volcanic eruption, contact the USGS to determine if you are within a volcano hazard zone, learn more about volcano hazards from some of the sources listed below, find out what emergency plans have been made by your community, and develop a contingency plan for you and your family.
(Editors: Interviews with volcanologists can be arranged by calling the USGS Public Affairs Office at 415-329-4000, or by calling the following volcanologists directly:
USGS Volcano Hazards Program:
Robert I. Tilling, Chief Scientist, 415-329-5228
Marianne Guffanti, Program Coordinator, 703-648-6708
Alaska Volcano Observatory: Terry Keith, Scientist-in-Charge, 907-786-7443
Cascades Volcano Observatory: Daniel Dzurisin, Scientist-in-Charge, 360-696-7826
Hawaiian Volcano Observatory: Donald A. Swanson, Scientist-in-Charge, 808-967-8819
Long Valley: David P. Hill, Scientist-in-Charge, 415-329-4795
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