3 Types of Volcanoes

Shield volcanoes are huge in size. They are built by many layers of runny lava flows. Lava spills out of a central vent or group of vents. A broad shaped, gently sloping cone is formed. This is caused by the very fluid, basaltic lava which can't be piled up into steep mounds.

Composite volcanoes, also called strato volcanoes, are formed by alternating layers of lava and rock fragments. This is the reason they are called composite.Strato-volcanoes often form impressive, snow-capped peaks which are often exceeding 2500m in height, 1000sq.km in surface, and 400km3 in volume. Between eruptions they are often so quiet they seem extinct. To witness the start of a great eruption requires luck or very careful surveillance. Composite volcanoes usually erupt in an explosive way. This is usually caused by viscous magma. When very viscous magma rises to the surface, it usually clogs the craterpipe, and gas in the craterpipe gets locked up. Therefore, the pressure will increase resulting in an explosive eruption.

A cinder cone is a steep conical hill formed above a vent. Cinder cones are among the most common volcanic landforms found in the world. They aren't famous as their eruptions usually don't cause any loss of life. Cinder cones are chiefly formed by Strombolian eruptions. The cones usually grow up in groups and they often occur on the flanks of strato volcanoes and shield volcanoes. Cinder cones are built from lava fragments called cinders. The lava fragments are ejected from a single vent and accumulate around the vent when they fall back to earth. The shape of a cinder cone can be modified during its (short) life. When the position of the vent alters, aligned, twin or secant cones develop. Nested,buried or breached cones are formed when the power of the eruption varies.

A volcano is a mountain with a vent. It erupts lava but when the lava is in the volcano, it is magma.

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Magma is molten rock that is found beneath the surface of the Earth, and may also exist on other terrestrial planets.

Lava is molten rock expelled by a volcano during eruption.

A fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt

The sudden occurrence of a violent discharge of steam and volcanic material