There are two types of volcanoes, strato-volcanoes and shield volcanoes. Both are characterized differently, for example, strato volcanoes have sleep slopes, shaped like a tall narrow cone, but shield volcanoes have gentle slopes, shaped like a low, wide cone. The eruptions can be devastating, an example would be mount vesuvius,which erupted in AD 79, killing over 10,000 to 25,000.
Strato volcanoes are the larger and more impressive volcanoes with a snow capped peak which can easily exceed 2500m in height. There are more strato volcanoes than there are shield volcanoes (60%) and they are larger. The structure of the shield volcano is large and consists of a lava chamber and a plug, which will cause a great explosion if blown. The sides are made of layered tephra (rock fragments and particles) and dried lava. Strato Volcano's have a thicker lava similar to putting a cap on a soda bottle and shaking it up. When the pressure becomes too immense, the plug releases and causes a heavy eruption which includes a pyroclastic flow. When the emitted Lava collects on the sides of the volcano it backs up and forms the steep.
A shield Volcano's lava is thinner and less viscous and is more free flowing, this explains how it never builds up pressure and only explodes violently if water enters the chamber. Because the lava does not back up, a shield volcanos sides are more spread out and less steep. They are composed of thousands of fluid lava flows that spread great distances, sometimes greater than 50 kilometres. Shield volcanoes are huge in size. 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. Shield volcanoes can be produced by hot spots which lay far away from the edges of tectonic plates. Making it unique and being part of their properties, the tallest volcano in the world is a shield volcano.
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