* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download File
Mount Rainier wikipedia , lookup
Sidoarjo mud flow wikipedia , lookup
Lōʻihi Seamount wikipedia , lookup
Itcha Range wikipedia , lookup
Axial Seamount wikipedia , lookup
Mount Garibaldi wikipedia , lookup
Mount Meager massif wikipedia , lookup
Llullaillaco wikipedia , lookup
Level Mountain wikipedia , lookup
Mount Pleasant Caldera wikipedia , lookup
Craters of the Moon National Monument and Preserve wikipedia , lookup
Mount Pinatubo wikipedia , lookup
Cerro Blanco (volcano) wikipedia , lookup
Mount Rinjani wikipedia , lookup
Wells Gray-Clearwater volcanic field wikipedia , lookup
Lascar (volcano) wikipedia , lookup
Mount Edziza volcanic complex wikipedia , lookup
Volcanology of Io wikipedia , lookup
Olympus Mons wikipedia , lookup
Cascade Volcanoes wikipedia , lookup
Mount St. Helens wikipedia , lookup
Silverthrone Caldera wikipedia , lookup
Shield volcano wikipedia , lookup
Nevado del Ruiz wikipedia , lookup
Mount Vesuvius wikipedia , lookup
Mount Pelée wikipedia , lookup
Volcanoes Not just one type • What are volcanoes? • Where do they form? • How do they erupt? • What are the different types of volcanoes Why does a volcano erupt? Volcanoes are often cone-shaped, but they can take other shapes too. The melted rock that spills out of the crater on the top of the volcano is called lava. The lava destroys everything in its path because it is very, very hot! A volcano erupts when magma and gases find a way to escape, so they burst to the surface through a vent. An eruption can be quite gentle or very violent. Where do volcanoes happen? Most volcanoes are formed on land, but there are some volcanoes that are on the ocean floor. Some of these volcanoes emerge from the water because they are very high. Europe Asi a North America South America Africa Map 1. The world patterns of volcanoes and earthquakes Australasia Did you know? Mount Kilauea, in Hawaii, is the most active volcano on Earth because it has been erupting since 1983! Pumice stone, which comes from volcanoes, is very light because it contains lot of tiny bubbles. If there are enough bubbles, then pumice stone can float on water! The word, ‘volcano’ comes from the name Vulcan, who was the Roman god of fire. Volcano facts • How many? 1511 volcanoes in last 10,000 years • The biggest? > 80,000 km3, Mauna Loa (Hawaii) • The highest? 6,887 m, Ojos del Salado (Chile) • The biggest eruption? 2,500 km3, Yellowstone, 2.2 Ma (USA) • First volcanologist? 79 AD - Pliny the Younger • Total deaths? 238,000 (1600-1982) Types of volcano Volcanoes can be active, dormant or extinct. • A volcano is active, or alive, when it erupts often. • When a volcano is dormant, or sleeping, it has not erupted for a long time – but it might in the future. • A volcano is extinct, or dead, when it hasn’t erupted for at least 100,000 years. GLOSSARY Bomb – a lump of rock thrown out in an eruption Crater – a deep hollow at the top of a volcano Crust – The top layer of the Earth Eruption – the release of gases, magma and rock from a volcano Lava – melted rock that flows down the volcano Magma – melted rock inside the Earth Molten – melted, liquid Vent – a crack on the side of a volcano where magma can escape •Layers of ash and lava •Secondary cone •Volcanic cone •Crater •Lava flow •Magma •Main vent •Magma chamber •Volcanic bombs, ash and gases Are all volcanoes the same? Compare the two volcanoes (compare means say what the differences/similarities are) Eruption patterns There are three different levels of eruption: 1. If it easy for the gases to escape, then the eruption is very gentle. However, the lava is very runny and can move very fast. 2. Gas builds up and lumps of rock (‘bombs’) and ash burst out of the volcano. This makes the lava thick and sticky. 3. This is the fiercest eruption of all because the gases and magma become trapped inside the volcano. This causes a huge explosion, which can be big enough to remove the top of the whole mountain! Composite Cone Mt St Helens - USA Crater Pyroclastic Flow The volcano is built up of alternate layers of LAVA and ASH. They can explode with great violence. Ash layer Lava Layer Conelet Dyke Flank eruption Lava Flow Crust Shield ( Basic) Cone Mauna Loa Hawaii -USA Shield Volcanoes are enormous features built up only from layers of lava. They produce lots of lava but they tend not to erupt violently. Layers of Lava Lava Flow 10,000m 250 miles Composite volcano to scale Ash and Cinder Cone Paracutin - Mexico Volcanic Bombs 3,000m Pipe The volcano is built up of layers of ASH. When it erupts it is normally with great explosive force. Layers of Ash and Cinder