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Volcanos When a volcano in Iceland erupted in April, it caused huge disruption in parts of Europe. Lots of British tourists were stranded abroad and couldn't get home because it was too dangerous for planes to fly through the huge ash cloud the volcano emitted. Volcanoes: the facts • A volcano is a piece of land (usually a mountain) which molten rock (magma) erupts from • They're like safety valves that release the pressure that builds up inside the Earth • 300 million, or 1 in 20, people in the world live within 'danger range' of an active volcano Lava that flows from • About 1,500 different volcanoes have erupted over volcanoes is so hot it the past 10,000 years, but only about 60 erupt each burns everything in its year. On any given day, there are about 20 volcanoes path erupting somewhere in the world • Some volcanoes are under the sea • In the past 500 years, 250,000 people have been killed as a direct result of volcanic eruptions • The Earth's rigid outer layer is made from huge slabs called tectonic plates that fit together like a jigsaw puzzle. When two of them collide, one is pushed below the other, causing melting at depth that leads to volcanic eruptions when the molten rock (magma) finds its way to the surface • Volcanoes can also erupt at sites where two plates are being pulled apart, like Iceland, or at special 'hot The world's largest active volcano is Mauna Loa in spots' like Hawaii • The world's largest active volcano is Mauna Loa in Hawaii Hawaii • Lava flows can reach 1,250 degrees Celsius and burn everything in their path - a glass thermometer would just melt if you tried to measure it • Ash and toxins from eruptions can be dangerous and cause lung damage, particularly for babies and old people • People often set up home on the slopes of volcanoes because the soil there is rich and fertile • 90% of all volcanoes are in the 'Ring of Fire' which is along the edges of the Pacific Ocean • The word volcano probably comes from the name of The volcanic eruption in Iceland Vulcano, which is an island off Sicily named after Vulcan, the Roman God of Fire The eruption in Iceland • It's in south-west Iceland, it's near the sea, and it covers around 40 square miles • It's 1,666 metres tall • The volcano has erupted TWICE. Once in March 2010, which meant 500 people were evacuated from the area, and then again in April (much more powerful than the March eruption) which caused Europe so much disruption • It's underneath a glacier which causes two problems: 1) flooding when the heat from the volcano melts all the ice, which is why those people were evacuated, and 2) it makes the eruption highly explosive. When the water leaked into the insides of the volcano, the magma turned the water to steam. The resulting explosion shattered the magma into tiny The Eyjafjallajökull fragments called 'volcanic ash' and shot them high volcano erupts in Iceland into the sky • The ash cloud reached 55,000 feet • Iceland is a volcanic hot spot on the Mid-Atlantic Ridge, which is the dividing line between the Eurasian and North American plates • There are 35 active volcanoes in Iceland • There is another volcano nearby and people are worried this eruption could set it off. It's called Katla The disruption caused by the volcano • British airspace was closed for six days, which meant no planes could fly at all • 120,000-150,000 Brits were stranded abroad, including loads of teachers and pupils on their Easter holidays • The disruption has cost airlines across the whole world £1.1 billion • 1.2 million passengers a day were affected by the closure British airspace was closed for six days CBBC - Newsround - Volcanoes (2011) More on the impact on residents Authorities moved 800 residents away from the Eyjafjallajokull glacier as rivers rose by up to three metres. Rognvaldur Olafsson, a chief inspector for the Icelandic Civil Protection Agency, said no lives or properties were in immediate danger. Emergency officials and scientists said the eruption under the ice cap was 10 to 20 times more powerful than an eruption that happened in the area late last month, and carried a much greater risk of widespread flooding. "This is a very much more violent eruption because it's interacting with ice and water," said Andy Russell, an expert in glacial flooding at the University of Newcastle in northern England. "It becomes much more explosive, instead of a nice lava flow oozing out of the ground." The volcano, about 120 kilometres east of Reykjavik, erupted March 20 after almost 200 years of silence. Pall Einarsson, a geophysicist at the University of Iceland, said magma was melting a hole in the thick ice covering the volcano's crater, sending water coursing down the glacier. Iceland's main coastal ring road was closed near the volcano, and workers smashed a hole in the highway in a bid to give the rushing water a clear route to the coast and prevent a major bridge from being swept away CBC News World (2010) Predicting and preparing for volcanoes It's not possible to prevent earthquakes and volcanic eruptions. However, careful management of these hazards can minimise the damage that they cause. Prediction is the most important aspect of this, as this gives people time to evacuate the area and make preparations for the event. Unfortunately volcanic eruptions and earthquakes cannot be prevented. Managing hazards such as earthquakes and volcanoes can be done by: prediction and preparation. Predicting eruptions As a volcano becomes active, it gives off a number of warning signs. These warning signs are picked up by volcanologists (experts who study volcanoes) and the volcano is monitored. Key techniques for monitoring a volcano Warning signs Monitoring techniques Hundreds of small earthquakes are caused as magma rises up through cracks in the Earth's crust. Seismometers are used to detect earthquakes. Temperatures around the volcano rise as activity increases. Thermal imaging techniques and satellite cameras can be used to detect heat around a volcano. When a volcano is close to erupting it starts Gas samples may be taken and to release gases. The higher the sulfur chemical sensors used to measure sulfur levels. content of these gases, the closer the volcano is to erupting. The techniques available for predicting and monitoring volcanic activity are becoming increasingly accurate. Volcanoes such as Mount St Helens in the USA and Mount Etna in Italy are closely monitored at all times. This is because they have been active in recent years and people who live nearby would benefit from early-warning signs of an eruption. However, as well as prediction, people need to be prepared for an eruption. Preparing for an eruption A detailed plan is needed for dealing with a possible eruption. Everyone who could be affected needs to know the plan and what they should do if it needs to be put into action. Planning for a volcanic eruption includes: creating an exclusion zone around the volcano being ready and able to evacuate residents having an emergency supply of basic provisions, such as food funds need to be available to deal with the emergency and a good communication system needs to be in place BBC GCSE Bitesize (2014) Some safety procedures when a volcano erupts • If you live near an active volcano, keep goggles and a mask in an emergency kit, along with a flashlight and a working, battery-operated radio. • Know your evacuation route. Keep gas in your car. If a Volcano Erupts in Your Area • Evacuate only as recommended by authorities to stay clear of lava, mud flows, and flying rocks and debris. • Avoid river areas and low-lying regions. • Before you leave the house, change into long-sleeved shirts and long pants and use goggles or eyeglasses, not contacts. Wear an emergency mask or hold a damp cloth over your face. • If you are not evacuating, close windows and doors and block chimneys and other vents, to prevent ash from coming into the house. • Be aware that ash may put excess weight on your roof and need to be swept away. Wear protection during cleanups. • Ash can damage engines and metal parts, so avoid driving. If you must drive, stay below 35 miles (56 kilometers) an hour. © 1996-2014 National Geographic Society