If the magma reaches the surface you get a volcano; with the ash, and the lava and the explosions. Over a long period, the magma cools to become cold, hard rock. Mountains and Volcanoes are somewhat similar but the major factor that makes them different is their formation. A mountain is formed due to various geological processes like movement and opposition of tectonic plates but a volcano is formed around a vent that allows magma to reach the surface of the earth.
Magma-formed mountains form when pressure from below forces the crust upwards and creates peaks, but the magma fails to reach the surface. Volcanoes, on the other hand, form from the accretion of lava after repeated volcanic eruptions. Most mountains form as the result of plate tectonics, although some were formed by magma welling up from the mantle without breaking through the surface. Teach your students about volcanoes with this collection of engaging material.
A volcano is a feature in Earth's crust where molten rock is squeezed out onto the Earth's surface. Along with molten rock, volcanoes also release gases, ash, and solid rock.
Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Image Volcanic eruption Volcanic eruptions can create colorful and dramatic displays, such as this eruption of this volcano in the Virunga Moutains of the Democratic Republic of the Congo. Photograph by Chris Johns. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
Media If a media asset is downloadable, a download button appears in the corner of the media viewer. Text Text on this page is printable and can be used according to our Terms of Service. During their formation, the magma has high viscosity thus cools fast and does not spread far from the vent. Stratovolcanoes erupt less frequently but once they erupt, their eruption is more violent than that of shield volcanoes.
Shield volcanoes have gently sloping cones. During their eruption, low-viscosity materials and basalt are emitted and these spread far from the vent. Therefore, shield volcanoes are not as steep as the stratovolcanoes. In some instances, magma may not reach the surface of the earth. Instead, magma pushes beneath the surface of the earth's crust causing overlying rock to rise.
Upon the cooling of the magma, a hardened rock is formed resulting to an uplifted area referred to as a dome mountain. Magma is liquid rock within a volcano and upon reaching the earth's surface it is referred to as lava. During an eruption, lava can have a temperature of up to degrees Celsius. Besides lava, a more dangerous flow known as pyroclastic flow occurs during an eruption. When a vent allows magma to well up from the Earth's mantle and reach the surface, it eventually cools around the vent, forming volcanic stone.
Multiple eruptions add to this rock accretion, gradually building up a cone centered around the volcanic vent. If the plate moves away from the hot spot that created the volcano, the volcano may become dormant. World View.
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