2. 1) TYPES OF VOLCANOES 2) WHAT IS MAGMA MADE OF?

3. Composition (What something is made of)  Determined by the where it is formed  “geologic setting” Determines what it is made from  Mixture of SiO 2, Fe, Mg and other elements.  Amount of SiO 2 in the magma determines:  Type  Viscosity  Gas release ability

4. What kind of rocks form? LavaMafic-DarkIntermediateFelsic-Light Rock TypeBasaltAndesiteRhyolite SiO 2 %45-5050-6060+ ViscosityLowMediumHigh TemperatureLower-700 CMediumHigher-1600 C Why is it called lava??? I thought it was magma…

5. Shield Volcanoes  Broader  Not explosive  Constant gas release  Why do you think it is not explosive (hmm)?  High Viscosity  Flows really well so you get broad short volcano

8. Cinder Cones  Steep  More explosive  Gases trapped  Viscosity  What do you think… Higher or lower than Shield?

10. Stratovolcanoes  Steepest  large and explosive  Symmetric  Gases trapped  Tallest  At subduction zones  Mt. Fuji, Japan  Mt. Pinatubo, Philippines  Mt. Rainier, Washington  Viscosity?

12. Guess What?!

13. Attention Check Time 1) If you want to make yourself a Hawaiian Shield Volcano at home what would be a good substitute for the viscosity of magma that it has? A) Syrup B) Water C) Molasses D) there shouldn’t be any magma 2) Which volcanoes are the most explosive? 3) Why are they so explosive (what are 2 things they have in common)? 4) Can you think of a way to make a volcano more explosive?