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Science
Earthquakes
Question | Answer |
---|---|
What are the forces in earths crust? | Tension, Compression, and Shearing |
How does Stress change earth's crust? | Stress adds energy to a rock. Rock may bend, stretch, or break. |
What is stress? | A force that acts on rock to change its shape or volume. |
What is tension? | The force that pulls the crust apart and thins the rock in the middle. |
What is compression? | The force that squeezes the rock together until it bends or folds |
What is shearing? | Stress that pushes a mass of rock in two opposite directions, slip past each other |
How do faults form? | When enough stress builds up in rock the rock breaks creating a fault |
What are normal faults? | Occurs when two plates pull apart, the hanging wall slips down under the footwall |
What are reverse faults? | Occurs when two plates push together and the rocks moves up over the footwall |
What are strike-slip faults? | The rocks on either side move past each other sideways with a little up and down motion |
How does plate movement create new landforms? | The forces of plate movement can change flat plain features such as anticlines and synclines, folded mountains, fault-block mountains,and plateaus |
How do folds form? | Folds are bends in rock that form when compression shortens in earths crust |
What are anticlines? | A fold in rock that bends into an upward arch |
What are synclines? | A fold in rock that bends downward into a V shape |
What are folded mountains? | The compression and folding of earths crust over a wide area |
How do folded mountains form? | When there is collision of two plates |
How do fault-block mountains form? | When a normal fault slips downward and the block in between stands above the surrounding valleys (tension) |
What is a plateau?How does it form? | Large area of flat elevated land that forms when forces in earths crust push up a mass of rock |
What are seismic waves? | Vibrations that travel through earth carrying energy released by an earthquake |
What is an earthquake? | The shaking and trembling |
What causes an earthquake? | Movement of rock beneath earths surface, that causes rock to slip or break |
What are the types of seismic waves? | S waves, P waves, and Surface waves |
What is a focus? | The area beneath earths surface where rock that was under stress begins to break or move |
What is an epicenter? | Surface directly above the focus |
What are P waves? | Compress and expand in the ground, arrive first, can travel through anything |
What are S waves? | Vibrate from side to side, arrive second, can only travel through solids |
What are surface waves? | Roll in the ground like ocean waves, arrive last, combination of s and p waves at the surface |
What is a seismograph? | Instrument that records and measures an earthquakes seismic waves |
What is the modified mercalli scale? | Rates amount of damage and shaking at any given location effected by an earthquake |
What is the richter scale? | Rates the size of an earthquake |
What is magnitude? | Size of an earthquake |
What is the movement of magnitude scale? | Rates the total amount of energy an earthquake releases |
How do you compare magnitudes? | Every one point increase is 32 times more energy +6 is great damage -5 is little damage |
How is a epicenter located? | Seismic waves |
How do seismograms work? | Seismic waves cause the drum to vibrate and in result the pen records the drums vibrations |
How are seismic waves measured? | The pen remains stationary while the paper moves |
What is a seismogram? | Pattern of lines produced by a seismograph |
What patterns do seismographic data reveal? | Where earthquakes occur around the world, that they occur along plate boundaries |
What is the earthquake risk in North America? | Earthquakes are most likely to occur on the west coast |
What is the ring of fire? | A ring of plate boundaries around the Pacific ocean |