How do volcanoes form

How Do Volcanoes Form?

Deep inside Earth, heat and pressure cause rocks to melt, forming liquid rock or magma. At this depth, some of the rocks would be already liquid, and others would need a small rise in temperature or small drop of pressure to melt and form magma. Decompression melting occurs thus when pressure decreases causing those igneous rocks to melt. Magma later rises towards the surface since it is lighter than the rocks that surround it. It takes several thousands or even millions of years for this magma to reach the Earth's surface and flow out of an opening called a vent. Once magma reaches the surface, we call it lava. This lava cools and becomes thus solid, forming layers of igneous rock around the vent. The steep-walled depression around a volcano's vent is the crater.

Questions:
1- What is magma composed of?
2- What factors influence the difference in magmas (highly fluid, pyroclastic ash...)?
3- Why does a descrease in pressure cause rocks to melt?

References:

• Grotzinger, J., & Jordan, T. (2010). Volcanoes. In W.H. Freeman and Company.
• Weston, M. (n.d.). Volcanoes. Retrieved from www.volcanoes.com
• Dr. Camp, V. (n.d.). How volcanoes work. Retrieved from http://www.geology.sdsu.edu/how_volcanoes_work/Home.html

Effects of Erruption

A village Destroyed After a Pyroclastic Flow

Volcanoes are thought to have direct dramatic effects on the lives of the people and their properties since hot lava flows tends to distroy everything in its path. Moreover, when lava takes the form of ash, its effects can be even more destructive as it can collapse buildings, blocks roads, and even cause lung disease. Pyroclastic flows, which represent the ash rushing down the side of the volcano, is very high in temperature, and is thus very dangerous. Thus, big eruptions require that people evacuate their towns, and to a certain point, even their cities, in order to survive.

Questions:
1- List the three types of Pyroclastic flow.
2- What can be the effects of pyroclasic ash?
3- In relying on the above information, what would you conclude to be the differences between lava and pyroclastic ash?

References:

• Grotzinger, J., & Jordan, T. (2010). Volcanoes. In W.H. Freeman and Company.
• Weston, M. (n.d.). Volcanoes. Retrieved from www.volcanoes.com
• Dr. Camp, V. (n.d.). How volcanoes work. Retrieved from http://www.geology.sdsu.edu/how_volcanoes_work/Home.html

What Are Volcanoes?

Volcanic Eruption

Volcanoes are created when matter from inside the Earth escapes to the surface. This material erupts in the from of lava, ash, or other materials that have built up around the openings of these volcanoes. A volcano can be found in many different shapes, but the most common is a known as the "Volcanic Mountain". Other forms will be discussed throughout the course material. Kilauea is one of the most active volcanoes in the world, located in Hawai. Moreover, the country is Iceland is also famous for its numerous active volcanoes.

Questions (click "comments" and type your answer):
1- Can you name any volcanoes?
2- How many volcanoes are loacted on Earth?
3- What is lava?

References:

• Grotzinger, J., & Jordan, T. (2010). Volcanoes. In W.H. Freeman and Company.
• Weston, M. (n.d.). Volcanoes. Retrieved from www.volcanoes.com
• Dr. Camp, V. (n.d.). How volcanoes work. Retrieved from http://www.geology.sdsu.edu/how_volcanoes_work/Home.html

Welcome To Our Class Blog

Welcome to our class Blog. Here you will be learning more about volanoes and all aspects related to their formation. I will also post announcements, homework assignments, and links to important websites related to the volcanoes.