| Chile volcano eruption forces mass evacuation | ||
Winds spread the ash towards neighbouring Argentina, darkening the sky in the ski resort city of San Carlos de Bariloche, a government official there said on Saturday, adding the city's airport had been closed. The eruption in the Puyehue-Cordon Caulle volcanic chain, about 920km south of the capital, Santiago, also prompted Chilean authorities to shut a heavily travelled border crossing into Argentina. 'Constant seismic activity' It was not immediately clear which of the chain's four volcanoes had erupted because of ash cover and weather conditions. The chain last saw a major eruption in 1960. Local media said the smell of sulfur hung in the air and there was constant seismic activity. "The Cordon Caulle [volcanic range] has entered an eruptive process, with an explosion resulting in a 10-kilometre-high gas column," ONEMI, the state emergency office, said. The government said it was evacuating 3,500 people from the surrounding area as a precaution. It was the latest in a series of volcanic eruptions in Chile in recent years. Chile's Chaiten volcano erupted spectacularly in 2008 for the first time in thousands of years, spewing molten rock and a vast cloud of ash that reached the stratosphere. The ash also swelled a nearby river and ravaged a nearby town of the same name. The ash cloud from Chaiten coated towns in Argentina and was visible from space. Chile's Llaima volcano, one of South America's most active, erupted in 2008 and 2009. Chile's chain of about 2,000 volcanoes is the world's second largest after Indonesia. About 50 to 60 are on record as having erupted, and 500 are potentially active. |
Info4 Volcanic eruptions
World Map of Volcanoes, Earthquakes, Impact Craters, and Plate Tectonics | ||
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This site supports and extends a 1x1.5 m wall map available through the "Order" link [above]. |
 | | The map is designed to show Earth's most prominent features when viewed from a distance, and more detailed features upon closer inspection. The back of the map zooms in further, highlighting examples of fundamental processes, while providing text, timelines, references, and other resources to enhance understanding of this dynamic planet. The main and polar maps, above, are interactive, inviting you to make your own regional map, using whichever "layers" you choose. Data for any volcano, earthquake, or impact symbol can be found via the "Identify" tool. |
Back of Map | ||
Most new crust forms at ocean ridge crests, is carried slowly away by plate movement, and is ultimately recycled deep into the earth�causing earthquakes and volcanism along the boundaries between moving tectonic plates. Oceans are continually opening (e.g., Red Sea, Atlantic) or closing (e.g., Mediterranean). Because continental crust is thicker and less dense than thinner, younger oceanic crust, most does not sink deep enough to be recycled, and remains largely preserved on land. Consequently, most continental bedrock is far older than the oldest oceanic bedrock (see back of map). The earthquakes and volcanoes that mark plate boundaries are clearly shown on this map, as are craters made by impacts of extraterrestrial objects that punctuate Earth's history, some causing catastrophic ecological changes. Over geologic time, continuing plate movements, together with relentless erosion and redeposition of material, mask or obliterate traces of earlier plate-tectonic or impact processes, making the older chapters of Earth's 4,500-million-year history increasingly difficult to read. The recent activity shown on this map provides only a present-day snapshot of Earth's long history, helping to illustrate how its present surface came to be. Both the front and back of this map illustrate the enormous recent growth in our knowledge of planet Earth. Yet, much remains unknown, particularly about the processes operating below the ever-shifting plates and the detailed geological history during all but the most recent stage of Earth's development. | ||
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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. When pressure from gases within the molten rock becomes too great, an eruption occurs. Eruptions can be quiet or explosive. There may be lava flows, flattened landscapes, poisonous gases, and flying rock and ash.
Because of their intense heat, lava flows are great fire hazards. Lava flows destroy everything in their path, but most move slowly enough that people can move out of the way.
Fresh volcanic ash, made of pulverized rock, can be abrasive, acidic, gritty, gassy, and odorous. While not immediately dangerous to most adults, the acidic gas and ash can cause lung damage to small infants, to older adults, and to those suffering from severe respiratory illnesses. Volcanic ash also can damage machinery, including engines and electrical equipment. Ash accumulations mixed with water become heavy and can collapse roofs. Volcanic ash can affect people hundreds of miles away from the cone of a volcano.
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.
Volcanic eruptions can be accompanied by other natural hazards, including earthquakes, mudflows and flash floods, rock falls and landslides, acid rain, fire, and (under special conditions) tsunamis.
Active volcanoes in the U.S. are found mainly in Hawaii, Alaska, and the Pacific Northwest. 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 the history of volcanic eruptions where I live?
How can I protect myself from a volcanic eruption?
Find a Volcano by Region
Smithsonian Institution, Global Volcanism Program
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All of the base maps in this section, for the world and volcanic regions, were generated using ER Mapper.
Citation Guidelines for this electronic version of Volcanoes of the World.
Chile volcano eruption forces mass evacuation
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