Answer Key Earthquakes and Volcanoes

[Pages:2]Reading Essentials

Answer Key

Earthquakes and Volcanoes

Lesson 1

Before You Read

1. agree 2. agree 3. disagree

Read to Learn

1. vibrations in the ground that result from movement along breaks in Earth's lithosphere

2. in the oceans and along the edges of continents where tectonic plates meet

3. a break in Earth's lithosphere where one block of rock moves toward, away from, or past another

4. strike-slip, normal, reverse 5. The epicenter is located on Earth's surface directly above the

focus. 6. Primary waves cause particles in the ground to move in a

push-pull motion. Secondary waves cause particles to move up and down at right angles relative to the direction that the wave travels. Surface waves cause particles in the ground to move up and down in a rolling motion. 7. It will stop. 8. These waves change speed and direction as they travel through different materials. 9. They discovered that S-waves cannot travel through the outer core. 10. The area contains hotter material than does the surrounding area. 11. Station 3 12. 16; 14 13. VII 14. by studying the probability that an earthquake will occur in an area, past earthquake activity, geology around a fault, population density, and building design in an area

After You Read

1. Possible answer: Primary waves cause particles to move like a coiled spring, whereas secondary waves cause particles to move up and down at right angles to the wave's direction.

Earthquakes and Volcanoes

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2. Students should circle the two horizontal arrows passing by each other going in opposite directions.

3. speed, travel time, distance

Lesson 2

Before You Read

4. disagree 5. disagree 6. disagree

Read to Learn

1. molten, or melted, rock 2. Volcanoes form when plates collide and one plate subducts,

when plates pull apart and magma rises through the openings, and above a hot spot where a rising current brings hot mantle materials to the surface. 3. The plate moves and the hot spot does not move. 4. The Ring of Fire surrounds the Pacific Ocean. 5. Students should highlight the string of active volcanoes that surrounds the Pacific Ocean from roughly the tip of Australia to the tip of South America. 6. magma composition and eruption style 7. magma's chemical composition and the amount of dissolved gases 8. mudflows that form when an eruption melts snow and ice on a volcano's summit and the meltwater mixes with mud and ash 9. Pyroclastic flows are very hot and move fast. 10. Ash and gases from eruptions block and reflect sunlight and cause global temperatures to decrease.

After You Read

1. Possible answer: A liquid with low viscosity flows more easily than a liquid with high viscosity.

2. explosive 3. Students should accurately list two facts they learned from

their partner's flash cards.

Reading Essentials

Earthquakes and Volcanoes

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