Situation Update No. 11
Posted:2011-06-04, 20:15:23 [UTC]
Ref.no.: VA-20110604-31011-MLC
Situation Update No. 11
On 2011-06-07 at 02:40:37 [UTC]
Event: Volcano Eruption
Location: MultiCountries Chile and Argentina Puyehue-Cordón Caulle Volcanic Complex (PCCVC)
Number of Evacuated: 3500 person(s)
Situation: An erupting Chilean volcano sent a towering plume of ash across South America on Monday, forcing thousands from their homes, grounding airline flights in southern Argentina and coating ski resorts with a gritty layer of dust instead of snow.Booming explosions echoed across the Andes as toxic gases belched up from a three-mile-long (five-kilometer long) fissure in the Puyehue-Cordon Caulle volcanic complex – a ridge between two craters just west of the Chilean-Argentine border that began erupting Saturday. Winds blew a six-mile-high (10-kilometer-high) cloud of ash all the way to the Atlantic Ocean and even into southern Buenos Aires province, hundreds of miles to the northeast. Authorities in Chile went house to house, trying to persuade stragglers near the volcano to leave because of an increasing danger of toxic gas and flash floods. By Monday, about 4,000 people had been evacuated from more than 22 communities. They began fleeing as swarms of earthquakes Saturday heralded the eruption and hundreds more fled Monday to shelters farther away. Some refused to leave, wanting to protect their homes and livestock. Chile's verdant lakes region is a center for dairy farming, with more than 9,000 cows and sheep. Deputy Interior Minister Rodrigo Ubilla said about 50 families in the Rininahue area refused to abandon their homes. "Everything is prepared with shelter and transportation for them to immediately leave the danger zone," added Vicente Nunez, director of Chile's emergency preparedness office, urging them to leave.
Just north of the complex of volcanoes, the city of Futrono and the communities of Lago Ranco and Entre Rios were particularly vulnerable to flash floods. Some people also refused to leave Mantilhue, along the Rio Bueno, or "Good River," just six miles (10 kilometers) from the eruption. And while the evacuation order wasn't yet mandatory, a group of Mapuche Indians said they would seek the regional governor's authorization to enter the area to pray for the volcano to stop erupting. Enrique Valdivieso, the director of Chile's National Geology and Mines Service, said the fissure was belching toxic gases and material that could clog rivers and force them to overflow. Spectacular displays of lightning flashed in the volcanic clouds during the weekend, and while the amount of ash falling east of the volcano subsided significantly by Monday, experts said it was too early to predict how long it will take before the volcano falls silent. Volcanic dust coated ski slopes above San Carlos de Bariloche and Villa la Angostura two weeks before the official start of the winter skiing season. The resorts' trade group said it was too early to say how it would affect the local economy, but for now, residents were told to stay indoors and tourists were asked not to come.
The Cordon Caulle is nearly 620 miles (1,000 kilometers) south of Santiago, in Chile's lakes region, just west of Bariloche. Authorities went on alert before the eruption Saturday when as many as 240 tremors an hour struck the region. The volcano's last major eruption was in 1960, shortly after a 9.5 magnitude earthquake, the most powerful in recorded history, struck Chile. Some scientists have said that last year's 8.8 quake in Chile increased the likelihood of volcanic activity due to shifts in pressure along the Earth's tectonic plates. The ash cloud first blew over Argentina and then circled back over Chile on Sunday. By Monday, however, prevailing winds had spread the ash eastward as far as Bahia Blanca, in southern Buenos Aires province on the Argentine coast. During the weekend, the volcano spat out pumice rocks nearly eight inches (20 centimeters) in diameter. Because airborne ash can severely damage jet engines, all flights between Buenos Aires and the Andean resorts of Bariloche, Esquel and Chapelco were canceled until June 12. Seven other airports in Argentina were closed through Thursday, effectively isolating the southern Patagonia region from the rest of the country. Aerolineas Argentinas also cancelled nighttime flights well to the north of the volcanos, from Buenos Aires to Santiago, Chile, and Mendoza, Argentina, as a precaution. LAN airlines suspended more than 35 flights from Chile to southern Argentina, and some highways in Argentina also were closed.
Across Argentina's southern midsection, schools were closed, routine government work was suspended and elective surgery were canceled as well. Also closed was the nearby border crossing of Cardenal Samore, where a twisting mountain road climbs through stunning arid valleys on the Argentina side before dropping through lush green forests and fields in Chile. Even when skies cleared in places Monday, the area was draped in an abrasive gray blanket. The 11-mile-long (17-kilometer-long) Cordon Caulle rises 5,900-feet (1,800 meters) above sea level between the Pueyehue and Nevada volcanoes, above a connected complex of molten rock. Chile has more than 3,000 volcanoes along its Andean spine, and 500 of these are considered geologically active. About 60 Of these have erupted in the last 450 years.
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
| Mediterranean and W Asia | Africa and Red Sea | Middle East and Indian Ocean | New Zealand to Fiji | Melanesia and Australia | Indonesia | Philippines and SE Asia | Japan, Taiwan, Marianas | Kuril Islands | Kamchatka and Mainland Asia | Alaska | Canada and Western USA | Hawaii and Pacific Ocean | México and Central America | South America | West Indies | Iceland and Arctic Ocean | Atlantic Ocean | Antarctica |
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.
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