Volcanic Features

Lavas and pyroclastics are usually andesitic to rhyolitic in composition. Due to the higher viscosityof magmas erupted from these volcanoes, they are usually more explosive than shield volcanoes. Stratovolcanoes sometimes have a crater at the summit that is formed by explosive ejection of material from a central vent.

What are the characteristics of a volcano?

Composite volcanoes

• Composite volcanoes are made up of alternating layers of lava and ash (other volcanoes just consist of lava).

• They are usually found at destructive or compressional boundaries.

• The eruptions from these volcanoes may be a pyroclastic flow rather than a lava flow.

What are volcanoes made out of?

Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.

What is in a volcanic eruption?

A volcano is a vent or chimney which transfers molten rock known as magma from depth to the Earth's surface. Magma erupting from a volcano is called lava and is the material which builds up the cone surrounding the vent. ...

A volcano is dormant if it has not erupted for a long time but could erupt again in the future.

What are volcanoes and how do they form?

Magma rises through cracks or weaknesses in the Earth's crust. When this pressure is released, eg as a result of plate movement, magma explodes to the surface causing a volcanic eruption. The lava from the eruption cools to form new crust. Over time, after several eruptions, the rock builds up and a volcano forms.

What happens when a volcano is about to erupt?

When magma reaches earth's surface it is called lava. It may pour out in gentle streams called lava flows or erupt violently into the air. Rocks ripped loose from the inside of the volcano or torn apart by the gas may be shot into the air with the lava. These rocks blown out of a volcano are called pyroclastic rocks.

What happens when a volcano is about to erupt?

When magma reaches earth's surface it is called lava. It may pour out in gentle streams called lava flows or erupt violently into the air. Rocks ripped loose from the inside of the volcano or torn apart by the gas may be shot into the air with the lava. These rocks blown out of a volcano are called pyroclastic rocks.

That's all, thank you!

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