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Earthquakes
Science
| Term | Definition |
|---|---|
| Stress | A force that acts on rock to change its shape or volume |
| Tension | |
| Compression | squeezes rock until it folds or breaks |
| Shearing | Stress that pushes a mass of rock in two opposite directions |
| Normal Faults | Tension in Earth's crust pulls rock apart |
| Hanging wall | The block of rock that lies above |
| Footfall | The block of rock that lies below |
| Reverse fault | has the same structure as a normal fault, but the blocks move in opposite direction |
| Strike-Slip fault | Rocks on either side of the fault slip past each other sideways,with little up or down motion |
| Anticline | A fold in rock that bends upward into an arch |
| Syncline | A fold in rock that bends downward to form a valley |
| Plateau | A large area of flat land elevated high above sea level |
| Earthquake | is the shaking and trembling that results from the movement of rock beneath Earth's surface |
| Focus | is the area beneath Earth's surface where rock that is under stress breaks, triggering an earthquake |
| Epicenter | The point on Earth's surface directly above the focus |
| P waves | First waves to arrive |
| S waves | After p waves comes secondary waves |
| Surface waves | Move more slowly than P waves and S waves, but they can produce severe ground movements |
| Mercalli Scale | was developed to rate earthquakes according to the level of damage at a given place |
| Magnitude | Number that geologists assign to an earthquake based on the earthquake's size |
| Richter scale | Rating of an earthquake's magnitude based on the size of the earthquake's seismic waves |
| Seismograph | The seismic waves are measured by a seismograph |
| Moment Magnitude Scale | A rating system that estimates the total energy released by an earthquake |