VOLCANO

• Volcanoes are classified into different types and have specific parts such as the volcano, the crust, the mantle, the magma chamber, and the layers of the Earth's crust.
• Volcanoes provide information about the interior of the Earth.
• Illustrations or models can be used to explain what happens when a volcano erupts.
• A volcano is an elevated landform with an opening at the top from which lava and other rock fragments, steam, gases, ash, heat, and other volcanic materials are ejected.
• The basic parts of a volcano include the fissure, the conduit, the vent, the crater, the flank, and the magma chamber or reservoir.
• There are three basic types of volcanoes: cinder cone volcanoes, composite volcanoes, and shield volcanoes.
• Cinder cone volcanoes are formed by highly viscous or thick, slow moving lava and have steep upper slopes and relaxed lower slopes.
• Cinder cone volcanoes have a small crater as their summit, and are packed with a large reservoir of magma caused by the heat and pressure of tectonic movement.
• When cinder cone volcanoes explode, an area of the volcano may collapse, forming a larger crater and depression called caldera.
• Most volcanoes in the Pacific Ring of Fire are stratovolcanoes.
• Stratovolcanoes or composite volcanoes may be formed from multiple eruptions thousands of years apart, layered lava and volcanic materials.
• During an eruption, lava is spewed out, followed by ash and pyroclastic materials that flow down the sides of the summit.
• Thick lava flows out and traps the ash and other materials on the steep slope.
• Heat from volcanoes may be tapped for human use.
• Lesser amount of dissolved gases lead to effusive, nonexplosive eruptions.
• Nuee Ardentes are clouds of hot ash and poisonous gasses that are ejected from a volcano.
• Volcanic soils are very fertile, known as Laterite soils, and are rich in minerals.
• Ash plume consists of water vapor, carbon dioxide, hydrogen gas, hydrogen chloride, hydrogen fluoride, hydrogen sulfide, and sulfur dioxide.
• Volcanic eruptions are characterized by the cloud of ash that comes out of the crater.
• Many dormant and active volcanoes attract hundreds of thousands of tourists each year, leading to spin-off industries such as business companies, restaurants, shops and hotels, generating a lot of employment.
• Lava from volcanoes can burn everything in its path.
• Granite, which is used in the construction industry, is formed by volcanic activity.
• The material flows down from a volcano, typically along a river valley.
• The ash and other volcanic products carried by the wind can travel not just to nearby communities but also other countries.
• Dissolved gases are emitted during volcanic eruptions.
• Build-up of thick magma coupled with large amounts of dissolved gases contributes to explosive eruptions.
• Strombolian is a violent type of eruption, featuring continuous ejection of magma and gas.
• Effects of volcanic eruptions include clouds of ash, dust, and gas reducing global temperatures by several degrees, emission of sulfur dioxide into the atmosphere leading to acid rain, and toxic, poisonous gases adding to the natural greenhouse effect.
• Volcanoes can create new land for human habitation, for example Iceland.
• Hawaiian is the least violent type of volcanic eruption, characterized by highly fluid or runny lava flowing out several vents, similar to Hawaiian volcanoes that create shield volcanoes.
• Lahar is a violent type of mudflow or debris flow composed of a slurry of pyroclastic materials, rocky debris and water.
• The magma of cinder cone volcanoes contains high levels of silica and low amounts of dissolved gas.
• Cinder cone volcanoes are formed by fluid lava that cools and hardens on the ground, have short-lived volcanic eruptions that spew lava high in the air, and as the lava cools on its descent, the rocks break down and form the steep conical landscape of the cinder volcano.
• Stratovolcanoes have a very large, steep-walled caldera on the summit.
• The magma of stratovolcanoes contains lower amounts of dissolved gases and silica.
• Volcanic eruptions are one of several forces that change the surface of Earth, caused by the heat from magma.
• Active volcanoes exhibit volcanic activity such as rumbling, crater glow, eruptions and earthquakes within the last 10,000 years, show no historical record of eruption in the past 10,000 years, and have the potential to erupt.
• Stratovolcanoes or composite volcanoes are formed by loose and fluid lava that flows over each other, are usually low and broad, and resemble a warrior’s armored shield or a gigantic blob.
• Shield volcanoes are formed by fluid lava that is ejected because of high pressure that builds up in the magma chamber, have short-lived volcanic eruptions that appear like a wild fountain show of a fiery lava spewed high in the air, and as the lava cools on its descent, the rocks break down and form the steep conical landscape of the cinder volcano.
• The magma of shield volcanoes contains lower amounts of dissolved gases and silica.