Volcanoes

3. An opening in the crust of the earth through which lava, ash,and gases flow
4. a mixture of hot solid particles suspended in water vapor and other gases
5. magma that contains 52-63% silica
7. magma that contains more than 63% silica
10. magma that erupts from a vent
12. We study volcanoes because they are
13. a huge crater-like depression
14. lava blobs and blocks larger than 64mm
16. loose pyroclastic materials and ash covering the ground
18. the Roman God of Fire
19. fast flowing lava that, when hard, has a shiny twisted rope appearance
21. Roman city destroyed by pyroclastic flow
23. a widened hole that magma erupts from
25. igneous structures related to volcanoes inside the crust
27. having to do with molten earth materials
29. the percentage of silica that is thicker and flows less easily
30. a mountain built from the accumulation of the material that flows from an opening

1. when lava breaks through the sides of the main cone
2. lava that is inside a volcano
6. silicon dioxide
8. a mudflow of volcanic ash mixed with water
9. vents in the ground where steam and other gases from volcanic activity escape
11. made of tiny angular glassy fragments
15. large spaces that magma has melted out
17. magma that contains less that 52% silica
20. slow flowing lava that, when hard, has a rough broken surface with sharp pieces of Rock
22. volcanoes that form on top of the Earth's crust
24. like ash but larger
26. cone when lava builds up
28. a depression at the top of the cone