volcanoes formalong plate boundaries lahars-mudflows made when volcanic debris mixes with water Lava -that is very runny probably has a low silica content. Changes in pressure and temperature in Earth’s crust and mantle cause magma to form. vent / fissure - magma and gases are expelled is a volcano. volcanic soil used for 3 farming shield volcano has gently sloping sides. 1. 2.

Subduction occurs when ____________________________________________________ Magma that explodes from a volcano and solidifies in the air is called _____________________ 3. 4. 5. 6. 7. 8. 9.

What can happen to global temperatures for several years after a volcanic eruption? The term


describes magma or igneous rock that is _____________________ The volcanoes of Hawaii and other places far from tectonic plate boundaries are known as Three types of volcanoes are _______________________________________ What are two uses of volcanic rocks? ___________________________________________________________ Rock begins to melt when _______________________ Columns of hot rock that rise through Earth’s mantle are called____________________ Essays 1. 2. 3. 4. How do temperature, pressure, and fluid content affect the formation of magma? What makes a pyroclastic flow particularly dangerous? How do volcanic rocks help plant growth? How do mid-ocean ridges form at divergent boundaries?

5. 6. 7. After 2,000 years of calm, Krakatau, a volcano in Indonesia, exploded violently in 1883. Ash flew 80 km into the air and covered an area of 800,000km 2 with pyroclastic debris. How do you think this mighty eruption affected the global climate?

Living near a volcano can be very dangerous. Why do you think so many people live close to volcanoes? The sides of Mount Rainier, in Washington, are covered with snow and glaciers. If Mount Rainier were to erupt explosively, what effects would you expect?


Use the following terms to complete the concept map below: mid-ocean ridges lahars mafic felsic divergent boundaries convergent boundaries