Test 10

8A and 8B

Monday, 03/16/09

Review.

1. FAULT is the boundary between two rocks sections that have been displaces relative to each other.

2. Plate tectonics theory states; that the Earth's crust is make up of rigid plates that move, and that mountains are formed when plates collide. Tectonic plates are responsible for building features on the Earth's surface, the motion of these plates causes continental drift.

The outer crust of the Earth is broken into seven large, rigid plates and several smaller ones. The continents and oceans ride on top of these plates.

3. Weathering is the process by which a rock is worn down by water, wind, or ice.

4. Erosion occurs when weathered fragments of soil, rock, and other materials are carried away.

5. The external forces of weathering and erosion are offset by internal forces that cause the land to be uplifted.

6. Rocks under stress either bend to form FOLDS, or beak to create FAULTS. Therefore FOLDS are bending of rock under stress.

7. Epicenter is the position on the surface of the Earth directly above the focus of an earthquake.

8. Focus o hypocenter is the point at which stress breaks the friction lock between two plates of the Earth's crust. The hypocenter can be far below the surface

9. Magnitude is the strength of an earthquake.

10. Richter scale of magnitude is a scale used to measure the strength of an earthquake based on the amplitude of seismic waves.

11. Seismographs are instruments that record the vibration of the Earth during an earthquake. Seismograph provide a method for determining an earthquake's strength.

12. Every earthquake is given a number that describes the magnitude, or strength, of the earthquake.

13. A volcano is an opening in the Earth's surface through which lava and other material erupt.

14. Lava is magma that emerges on the Earth's surface.

15. Magma is molten rock that triggers earthquakes and creates volcanoes as it rises within the Earth.

16. Volcanoes generally occur along plate boundaries. Most volcanoes are created when plates collide . Some are formed when two plates move apart, when the plates separate, magma move up from below to fill the gap. Other volcanoes, called hot spot, do not occur at plate boundaries, instead they are found at points in the Earth's crust where large amount of magma are being formed, the magma rises and pushes through the plate, forming a volcano.

17. The severity of of an eruption is determined by the bases in the magma. If the gases can escape gradually, there is usually no explosion.

18. Rocks are classified into three groups based on the way rocks were formed.: Igneous, Sedimentary, and Metamorphic.

19. Igneous rock is a rock formed by cooling and solidification of magma or lava (formed when molten rock cools).

20. Igneous rocks that form on the surface of the Earth are called extrusive or volcanic rocks ( formed from the molten lava that flows onto the surface of the Earth. When cooling of molten rocks occurs deep within the crust, the igneous rock formed is called intrusive, or plutonic rock ( formed from slowly cooling magma deep within the Earth's crust).

Answer.

1. Why earthquakes occur more often in certain areas?

2. How are most earthquakes caused?

3. Describe how the formation of folds and faults can result in mountains.

Solve.

4. How much stronger is an earthquake that is 6.4 in the Richter scale than an earthquake with a magnitude of 4.4??

5. How much weaker is an earthquake with a magnitude of 5.5 than an earthquake with a magnitude of 8.5??

5. Compare and contrast the the three types of volcanoes that occur along plate boundaries (Shield, Cinder cone, and composites).

6. List the most abundant extrusive and intrusive rocks. How are they formed?

7. Magnitude of volcanoes with moderate to slight damage.

8. How many earthquakes with great damage are recorded each year?