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Earthquakes and Volcanoes Review

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1 Earthquakes and Volcanoes Review

2 Describe the following types of plate boundaries, the stress associated with each one of them, and what types of events or features can occur at the boundary: The three types of boundaries are: 1. Convergent – plates are moving towards one another or colliding (compression) – creates mountains 2. Divergent – plates are moving apart (tension) – creates rift zones 3. Transform – plates are sliding horizontally past one another (shearing) – causes earthquakes

3 What is the mid-ocean ridge and at what type of boundary does it occur?
The mid-ocean ridge is a long under-sea mountain chain that forms along the floor of the major oceans. This is usually where new ocean floor is made due to it being a divergent boundary.

4 What is deformation? Deformation is the change in shape of the land due to pressure being applied. Deformation is NOT always bad because it does not always lead to destructive results.

5 What is stress, and what does it cause?
Stress is the amount of force per unit area that is placed on a given area or material. Three types of stress are : Tension, shearing, compression When stress is applied to rocks, folding and faulting takes place. This means the rocks bend or break.

6 List and describe the three different types of stress that can occur to the Earth.
1. During compression, rocks are pushed together (convergent boundary) and form mountains. 2. During shearing, rock pushes in different horizontal directions (transform boundaries) causing a rock to thrust or tear apart. This causes earthquakes. 3. Tension is stress that occurs when forces act to stretch an object (divergent boundaries). This can cause sea-floor spreading or rift valleys.

7 Where do earthquakes occur?
MOST earthquakes occur at tectonic plate boundaries.

8 What is a fold? A fold when stress is applied to a material and causes the material to bend.

9 What is a fault? A fault is when stress is applied to a material and causes the material to break. Faults occur with more stress or faster applied stress while less stress creates folds.

10 Explain what the magnitude of an earthquake and how is it determined.
Magnitude is the strength of an earthquake. Magnitude is determined by the seismic waves that are detected by a seismograph. Intensity is the amount of damage caused by an earthquake

11 What scale is used to measure the strength of an earthquake?
The scale used to measure earthquake magnitude (strength) is the Richter Scale.

12 List and describe the three types of seismic waves.
Seismic waves – wave of energy that travels through the earth and away from the earthquake’s focus in all different directions. Body Waves (P-waves and S-waves) and Surface waves Continued on next slide……

13 P-waves are primary waves or the first waves sent out during an earthquake. They are the fastest. **They can travel through solids, liquids, and gases. S-waves are also called shear waves or secondary waves. They can travel ONLY through solids. Surface waves are the seismic waves that do the most damage.

14 What is the difference between the epicenter and focus of an earthquake?
The focus is where the earthquake starts in the earth’s body while the epicenter is directly above the focus on the earth’s crust.

15 Give three examples of ways to protect yourself during an earthquake.
To stay save during an earthquake: 1. Crouch down under a table or something sturdy and cover your head. 2. If outside, lie face down with your head away from buildings, power lines, and trees. 3. If in a car, pull over but remain inside.

16 Why can earthquakes not be predicted by geologist?
Earthquakes can not be predicted because seismologists do not know when or where tectonic plates are going to move next.

17 Where do volcanoes form?
Most volcanic belts form along tectonic plate boundaries. Many form along the Pacific plate on the ocean floor. However, they also occur at hot spots where magma rises through faults in the earth

18 Why does magma flow up through
Magma is hot, molten rock that is beneath earth’s surface that is pushed upward due to the pressure beneath Earth’s surface and the fact that the magma is less dense.

19 What type of alternative energy resource is created by volcanoes?
Groundwater that is heated by magma gets it’s energy from Earth’s core, this is a form of geothermal energy.

20 What is the Ring of Fire? The Ring of Fire is a major earthquake and volcano zone that extends nearly all the way around the edge of the Pacific Ocean.

21 What can you conclude about the relationship between earthquakes and volcanoes?
Earthquakes and volcanoes are all due to heat pressure beneath Earth’s surface. They are created when tectonic plates move. They both form new landforms. Energy is associated to both occurring.


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