What is a volcano? Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits.

VOLCANOES http://youtu.be/wu1v1cgS9oU RING_OF_FIRE - a zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean.

Mid-ocean ridge volcano

Rifting, Diverging Boundary, Sea-floor spreading

Surface Volcanoes

Cinder cone – What’s it made of?

Shield volcanoes-basaltic

Composite Volcano

Composite volcanoes in North America Mt. Rainier Mt. Baker

Mt. St. Helen’s before

Mt. St. Helen’s after

A pyroclastic density current is a fast-moving current of hot gas and rock, which reaches speeds moving away from a volcano of up to 450 mph. The gas can reach temperatures of about 1,000 °C (1,830 °F). This heat can melt the snow that has accumulated at the top of the volcano and create a lahar.

If dust particles, ash and/or other aerosols are added to the atmosphere atmospheric transparency decreases and insolation may be blocked. (bye bye dinos, hello Frankenstein) Precipitation may help to clear the atmosphere. How?

This might be a good resource for your project foreither side!!!! When Mount Pinatubo in the Philippines erupted in 1991, it emitted millions of tonnes of SO2 that cooled the Earth slightly for the next few years. This might be a good resource for your project foreither side!!!! http://www.climatecentral.org/news/volcanoes-may-mask-lost-warming-15683

http://www.fs.fed.us/gpnf/volcanocams/msh/ Lahar These lethal mixtures of water and ash have the consistency of wet concrete.

HOT SPOTS http://www.wwnorton.com/college/geo/egeo2/content/animations/2_6.htm

Caldera Volcano

http://www. ouramazingplanet http://www.ouramazingplanet.com//405-yellowstone-national-park-old-faithful-super-volcano.html

1 The reflection of sunlight by volcanic dust might cause decrease in temperature. 2

3 4

5 The Great Rift Valley Rifting of Earth's crust in eastern Africa began during the Neogene Period as the Ethiopian and Kenyan Domes formed. These two huge domes were created as Earth's mantle pushed up the overlying crust. As the crust was forced upward, the resulting tension cracked the crust, resulting in the eruption of volcanoes and the formation of large rifts. The crust continued to pull apart, forming rift valleys. These valleys have become deeper and are currently becoming filled with sediments, igneous rock, and water. Rift valleys can emit carbon dioxide and methane into the atmosphere. How can this type of volcano cause global surface air temperatures to increase? They emit carbon dioxide and methane which are greenhouse gases. Greenhouse gases trap infrared rays in our atmosphere causing temperatures to rise.

6 Based on the age pattern of the calderas shown on the map, in which compass direction has the North American Plate moved during the last 16 million years? WSW or SW

7

8 Based on the age of the bedrock of the Galapagos Islands, in which direction does the tectonic plate containing the islands appear to be moving away from the Galapagos Hot Spot? Southeast or south

The End