What are Volcanoes?

Yarisa Castillo- Earth Science - Period 4

What are Volcanoes?

A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods. Volcano eruptions have been known to knock down entire forests. An erupting volcano can trigger tsunamis, flash floods, earthquakes, mudflows and rockfalls.

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Where can you find volcano's?

Most volcanoes are found near subduction zones and mid-ocean ridges. This explains why the map of volcanoes on Earth matches so well the map of tectonic plates. On the other hand, some volcanoes are located in remote places like in the middle of the Pacific plate (Hawaii), thousands of kilometers away from the nearest plate boundary.

Volcanoes in the United States
Volcanoes in Hawaii
Volcanoes in Europe
Volcanoes in South America

how do volcanoes affect humans positively and negatively?

Volcanoes affect negatively in many ways, some are good, some are not. Some of the bad ways are that houses, buildings, roads, and fields can get covered with ash.

Volcanoes affect positively in any ways, the ash serves a good purpose for you plants and crop the ash helps your plants grow and keeps them healthy

what are the different types of volcanoes?

Cinder cone volcanoes (also called scoria cones) are the most common type of volcano and are the symmetrical cone shaped volcanoes we typically think of

Stratovolcanoes are also called composite volcanoes because they are built of layers of alternating lava flow, ash and blocks of unmelted stone.

Shield volcanoes are huge, gently sloping volcanoes built of very thin lava spreading out in all directions from a central vent.

Lava domes are built up when the lava is too viscous to flow. A bubble or plug of cooling rock forms over a fissure

Why do volcanoes erupt?

A volcano erupts when the pressure within the molten magma below the surface becomes stronger than the strength of the rocks on the surface that make up the volcano. The magma then finds the path of least resistance to the surface and erupts. That pressure comes both from the buoyancy of the magma and from gas bubbles inside the magma that want to expand. The magma pressure comes from the expansion of gas bubbles that are within the magma. The heat source for all erupted materials comes from natural radioactive decay within the Earth. The concentration of radioactive elements in the Earth is not really very high, but the volume of the Earth is great enough so that there is enough of a contribution of heat from the decay to produce melting. The material that melts (magma) has a lower density and it migrates to the surface to erupt.

Why are some volcanoes more explosive then others?

Different magmas have different chemical compositions and different viscosities. "Viscosity is the scientific word for stickiness. A basaltic magma has a lower viscosity than a silicic granitic magma, so a volcano with a silicic magma is more explosive.

Where is the volcano Olympus mons located?

Olympus Mons is a shield volcano on Mars and it is the largest volcano in the Solar System. Located in the Tharsis region of the planet along with three other large volcanoes, Olympus Mons measures an incredible 27 km in height and is 3 times taller than Mount Everest.

Are volcanoes dangerous?

There are several reasons why volcanoes are so dangerous. One of the reasons is the lava produced by volcanoes can kill people. The emission of ash and dust by volcanoes can also cause breathing problems to people. Volcanoes can also give off poisonous gases that are harmful to the environment and living organisms.

What's inside a volcano?

The interior part of a volcano is made of three layers known as the crust, mantle and the core. Inside a volcano there is also a molten rock, which is found beneath the surface of the earth and normally erupts after a certain period.

How many volcanoes are there?

The exact number of volcanoes is unknown. It also depends on the definition of a "volcano": for instance, there are "volcanic fields" that comprise hundreds of individual eruption centers (such as conder cones, maars, shield volcanoes) that are all relataed to the same magma chamber and that may or not be counted as a single "volcano". There are probably millions of volcanoes that have been active during the whole lifespan of the earth.


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