Chapter 3 Test

Cones, Eruptions, and Pyroclasts




1. ___Lava  A. Rough and fragmented lava flows
2. ___Pahoehoe  B. The most explosive eruption type. Ash plumes may reach 50,000 feet.
3. ___Plinian  C. Molten rock on the surface of the Earth
4. ___Hawaiian  D. Large pyroclasts-over 2 inches long with a rounded shape
5. ___Aa  E. Smooth and ropey lava flows
6. ___Low Viscosity  F. Thin and runny magma that usually erupts quietly with large amounts of lava.
7. ___Bombs  G. Eruption type in which thin and runny magma reaches the surface of the Earth through the main vent and fissures.

8-9. Name two reasons that volcanic eruptions occur.

10-15. Name and draw the three kinds of volcanic cones.

16. What is a hot spot?

Fill in the blank with the correct answer. Use the following words to complete the blanks. Dust, Lava Tube, Mantle Plume, Ash, Caldera, Pyroclastic Flow, Blocks.

17. A large rough edged, angular pyroclast that is ejected during a volcanic eruption is called a _______________________.

18. A______________________ is a bowl-shaped depression caused by a volcanic eruption in which the top of the volcano collapses.

19. The smallest of the pyroclasts are called ___________________. They may stay in the atmosphere for years.

20. A ____________________ forms when the surface of the lava cools and hardens, while the molten interior flows through and drains away.

21. __________________ is the second smallest pyroclast. This material along with lava builds stratovolcanoes larger with repeated eruptions.

22. A ____________________ is very hot, solid rock that rises through the mantle and will become magma as it reaches the surface of the Earth. They form hot spots.

23. A_________________________ is a very hot, twirling mixture of ash, small pieces of pumice and other pyroclasts that are heavier than air and move down a volcano at high rates of speed.