Chapter 13 Study Notes

1. Chapter 13Study Notes Volcanoes

2. 1 • A _______ cone is rarely more than a few hundred meters high, with slope angles up to 40°, and formed from ______ eruptions. • cinder • explosive

3. 2 • A large circular depression that forms when the magma chamber below a volcano partially empties, causing the ground above it to sink, is called a ______. • caldera.

4. 3 • A _______ forms on the ocean floor in a _________ zone. • trench • subduction

5. 4 • An area of volcanic activity ____ from a tectonic plate boundary is called a ________. • far • hot spot.

6. 5 • Any activity that includes the movement of ______ to Earth’s surface is called ________. • magma • volcanism

7. 6 • ________ volcanoes are also known as _________. • Composite • stratovolcanoes

8. 7 • _______ eruptions are produced by ____, sticky lava with high viscosity and a high volume of trapped gases. • Explosive • thick,

9. 8 • ______ is cut by a fissure breaking it into two parts. • Iceland

10. 9 • If the temperature of rock rises ______ the melting point of the minerals the rock is composed of the rock will ____. • above • melt.

11. 10 • _____ plutons that can cover an area as large as 100 km2 are called ________. • Large • batholiths.

12. 11 • ____ is magma that flows onto Earth’s _____. • Lava • surface.

13. 12 • ____ is liquid rock produced _____ Earth’s surface. • Magma • under

14. 13 • Magma that is rich in _____ and silica is called ______. • feldspar • felsic

15. 14 • Magma that is rich in ______ and iron is called ___. • magnesium • mafic.

16. 15 • _____ lava forms on a _________ ridge. • Pillow • mid-ocean

17. 16 • _______ are igneous rock formations created when magma ____ __ reach Earth’s surface, but cools and solidifies ____ the crust. • Pluton • does • not • inside

18. 17 • Pyroclastic material ___ than 0.25 mm in diameter is called volcanic ______. • less • dust

19. 18 • _____ eruptions are produced by _____ lava with low viscosity and few trapped gases. • Quiet • runny

20. 19 • The eruption of Mount _________ was an ________ eruption. • St. Helens • explosive

21. 20 • The Pacific ____ __ ____ is both a major earthquake zone and volcano zone. • Ring • of • Fire

22. 21 • Three type’s volcanoes are _______, _____, and ______ cone. • composite • shield • cinder

23. 22 • Volcanic ___, ____, blocks, _____, and lapilli are all _______ materials. • ash • dust • bombs • pyroclastic.

24. 23 • Volcanic _____ may be signaled by a change in ______ activity. • eruptions • earthquake

25. 24 • When an ______ volcano erupts, the magma cools quickly, forming _____ lava. • underwater • pillow

26. 25 • When lava cools rapidly, a crust forms on the surface of the flow. If the flow continues, the crust _______ and forms volcanic rock known as ________. • wrinkles • pahoehoe.

27. 26 • When oceanic lithosphere _____ beneath oceanic lithosphere, an island ____ forms. • subducts • arc

28. The End!!!