JJ Ms. Kee

A volcano is one of the most destructive things on earth. Magma is extremely hot rock that is formed in the mantle. The magma can burn through almost anything. There are over a hundred volcanoes on earth and a lot on Mars.

There are many types of volcanoes and they erupt in different ways. A volcano is a mountain that releases magma and gas. A volcano is a vent from the mantle to the crust and the magma comes to the surface and becomes lava. Volcanoes are formed by a crack in the crust. The magma of a volcano can be hot, sticky, runny or gassy. Magma can be grey or red. When it is grey it is hard and dry, when it is red it is hot and runny.

There are volcanoes in all shapes and sizes. A shield volcano is formed by runny lava. The composite volcano is formed by many layers of ash. Cinder cone volcanoes are formed by ash and dust piling up. A conical volcano is formed by ash. The dome volcano is formed by sticky lava. Caldera volcanoes are formed by a volcanic explosion and a fissure volcano has no elevation. All of the volcanoes are destructive or gentle in their own ways.

All volcanoes erupt in different ways. The weakest eruption is a vent eruption. The most powerful is called an effusion eruption. Tephra is dried ash, lava and rock. Ryolite is the most destructive magma. It moves very fast and is very hot. When Mount Vesuvius erupted it sent ash twelve miles into the air. Composite volcanoes erupt through narrow cracks in the volcano called slits. The cone volcano erupts slow moving magma and the Stromboli volcano spits out runny lava. Volcanoes erupt in many different or strange ways.

An earthquake is one of the many things that can start an eruption. Pressure in the crust can start an eruption. The pressure increases if magma stays in the magma chamber which is a place in the volcano where the magma stays before an eruption for a long time. When the magma temperature reaches 1500 degrees Fahrenheit or more it will come out. Before the eruption the volcano releases bubbles that hold dioxide. Hotspots in the ground heat the magma so it is more powerful.

There are good and bad effects from an eruption. The lava can burn trough forests and destroy animal homes. It may destroy towns or islands. An eruption can cause fatalities, like the gas choking people. The ash from the volcano can make the ground fertile. Around Mount Vesuvius there are annual grape harvests. A volcano can create an island. Sometimes the wind of the eruption spreads seeds around. Volcanoes are usually very helpful.

There have been many deadly volcanoes over time. When Mount Thera erupted it started 200 mph. waves in 1500 B.C. Mount Pelee killed 34,000 people in Martinique in 1902. Krakatoa created a tsunami which destroyed towns along the coast in 1883. In the Philippines the volcano called Mayon has had over 18 eruptions in its life. Santorini covered Surtsy in ash and lava. Mount Vesuvius buried Pompeii and Herculaneum in ash and lava. Those are just a few of the many destructive volcanoes over time.

Volcanoes usually form in certain places. There are many volcanoes formed around “the ring of fire,” which is an area in the Pacific Ocean where plates meet. Volcanoes usually form over an area where one tectonic plate goes under another one. A lot of volcanoes form over hot spots. Many volcanoes are in water because the earth is mostly water. Volcanoes usually never form in an unexpected place.

Before the eruption there are usually many signs. The ground around the volcano will increase in heat or the shape of it will change. Animals become restless and snakes move to the mountains. Wells dry up. Volcanoes usually release sulfer. Warning signs help scientists find out when a volcano will erupt.

Volcanoes are forming every year. They are in every continent except Australia. Volcanoes will probably never stop forming.
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