Volcanoes

Highly fluid lava hardens into smooth, folded sheets of rock called pahoehoe. Stickier lava cools into rough, jagged sheets of rock called aa. Pahoehoe and aa cover large areas of Hawaii, where the terms originated. The stickiest lava forms flows of boulders and rubble called block flows. It may also form mounds of lava called domes.

Volcanoes need to be on top of a hot spot to erupt. A hot spot is a place on the Earth’s crust that magma from the mantle has broken through the crust. The magma pushes up through the crust and keeps pushing until there is a hole in the top of the mountain and when pressure builds up, it erupts out the top in a volcanic eruption. Another way it is formed is when the magma breaks through the surface of the Earth and it keeps coming out and erupting until a mountain is formed. The volcano erupts over and over again if it stays active.

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. In another definition it is a mountain That has a passage to the underground molten seas of rocks , when the pressure increases on this molten seas it causes eruption gases and molten rocks shoot up through a hole in the top of the mountain and fill the air with lava fragments . This eruptions cause a leatral blasts ,lava flows , hot ash flows and many other disaster .

Lava domes are created by small masses of lava which is too thick to travel far . Lava dome grows by lav expansion within the volcano , according to Universe Today . Cinder cone volcanoes are formed by lava fragments which land near a volcano vent to eventually create a circular shaped cone with a crater on top , according to Universe Today . Cinder cone volcanoes are the most common type of volcano . One type of volcanic eruption is when magma rises through the surface and comes out of a vent as a lava flow this is called an effusive eruption.

Sometimes this magma slowly works it’s way towards the upper surface of earth. Internal pressure builds up and results into a volcanic eruption. As the volcano erupts, ash and lava get deposited everywhere. The lava cools slowly being a poor conductor of heat. The lava continues to flow in its liquid state, however once it cools down, it hardens and remains stuck to the underlying soil or rocks.

Toxic gases and rocks shoot up through the opening, overflowing the air with hot lava fragments. This can bring floods, avalanches, and can even provoke tsunami and earthquakes. How are they formed? Volcanoes are created when magma from within the Earth's crust rises to the surface. At the surface of the volcano, the manga erupts to form lava flows and ash deposits.

Volcanoes are made up of different layers of the earth. Many things can occur after a bad eruption. There are 3 main things that can happen. They are Hot Springs, Calderas and Mud spots.Hot Springs occur when magma beneath the surface heats up the water in the cracks overlying rocks. Calderas happen when a massive blast of lava empties a volcano's magma chamber and causes the volcano to collapse on itself.

Volcanoes What a volcano is Volcanoes are mountains that open below the surface of the earth to a pool of molten rock. Eruptions occur when there is a build-up of pressure. When there is an opening, gases and rock shoot out of the volcano and can also spill over and/or fill the air with fragments of lava. Lateral bursts can be caused by the eruptions, as well as hot ash flows, avalanches, falling ash, lava flows floods and mudslides. Entire forests have been known to get knocked down by volcanoes erupting.

After significant time, the hard lava forms a volcanic mountain. Volcanoes can form in many different sizes and shapes. They can look like a cone, have steep looking flanks, or look as if they were long cracks in the earth’s crust. (Plummer et al., 2000). If the mountain is very tall, then there is a greater chance that it was formed from past eruptions.

Volcanoes Volcanoes are one of the most destructive yet fascinating geological land forms in our natural environment. They consist of a fissure in the earth's crust above which a cone of volcanic material has accumulated. The cone is formed by the deposition of molten or solid matter that flows from the interior of the earth through an indented vent, called a crater, which is found at the top of the cone. In this report I will discuss different states of volcanic activity, different forms of volcanoes and their properties and locations. Some volcanoes are more active than others.