Class 6

The Three Classic Types of Volcanoes Cinder Cone Volcanoes. Composite Volcanoes (Stratovolcanoes) Shield Volcanoes.

How long do volcanoes erupt for?According to the catalog “Volcanoes of the World” by Smithsonian Institution volcanologists Tom Simkin and Lee Siebert, 9 percent of eruptions end in less than one day, 16 percent within two days, 24 percent within one week, 30 percent within two weeks, 43 percent within a month, 53 percent within …

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As more magma enters the chamber, pressure builds, until the magma is pushed up through a pipelike vent and erupts on to the Earth’s surface. The eruption can be so forceful that the magma is blasted into the air, breaking into billions of pieces. These come in all sizes, from fine dust to large rocks.

Although there are several factors triggering a volcanic eruption, three predominate: the buoyancy of the magma, the pressure from the exsolved gases in the magma and the injection of a new batch of magma into an already filled magma chamber.

Volcanoes have done wonderful things for the Earth. They helped cool off the earth removing heat from its interior. Volcanic emissions have produced the atmosphere and the water of the oceans. Volcanoes make islands and add to the continents.

Volcanoes spew hot, dangerous gases, ash, lava, and rock that are powerfully destructive. People have died from volcanic blasts. Volcanic eruptions can result in additional threats to health, such as floods, mudslides, power outages, drinking water contamination, and wildfires.

When volcanoes erupt they can spew hot, dangerous gases, ash, lava and rock that can cause disastrous loss of life and property, especially in heavily populated areas. Volcanic activities and wildfires affected 6.2 million people and caused nearly 2400 deaths between 1998-2017.

There are four types of eruptions with properties determined mostly by the silica content of magma, and the amount of gas it contains. In order of increasing explosiveness, these are Hawai’ian, Strombolian, Vulcanian, and Plinian eruptions.

The melted rock, or magma, is lighter than the surrounding rock and rises up. This magma collects in magma chambers, but it is still miles below the surface. When enough magma builds up in the magma chamber, it forces its way up to the surface and erupts, often causing volcanic eruptions.

A volcanic eruption is when lava and gas are released from a volcano—sometimes explosively. The most dangerous type of eruption is called a ‘glowing avalanche’ which is when freshly erupted magma flows down the sides of a volcano. They can travel quickly and reach temperatures of up to 1,200 degrees Fahrenheit.