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4 - Earthquakes
Earthquakes
| Term | Definition |
|---|---|
| P waves | Waves that travel the fastest and don't do any damage. |
| Fault | Place where 2 plates meet to create earthquake. Most famous one is in California. |
| Focus | Point in the earth's crust where an earthquake begins |
| Moment Magnitude Scale | more accurate than richter scale, combines seismograph readings and rock movement. |
| Modified Mercalli Scale | Records visual damage as an indication of strength, 12 grades on the scale. |
| Animal Behaviour (Predicting Earthquakes) | Not scientific. Animals can detect P waves which humans cant & they react to them. |
| Historical Records (Predicting Earthquakes) | General prediction, unreliable. Earthquake once every 100 yrs = 10% chance every decade. |
| Rock Stress (Predicting Earthquakes) | Most reliable but not exact prediction. Use strainmeters, tiltmeters, Satellite/GPS, siesmographs. |
| Foreshocks | Tremors before earthquake happens |
| San Andreas Fault | Most famous fault line in the world |
| The Big One | Large earthquake that is predicted to occur before 2032 along San Andreas Fault. |
| Rift Valleys | Where earthquakes occur when convection currents split the continent apart in places such as the East African Rift Valley. |
| Seismograph | Equipment used to measure strength of earthquake |
| Richter scale | Readings from a seismograph that measures the magnitude (strength) of an earthquake. |
| Tsunami | Destructive wave caused by an underwater earthquake. Japan 2011. |
| Elastic rebound | It is the most common cause of earthquakes, as layers of rock are exposed to pressure from opposite sides. |
| What year did the Haitian earthquake happened | The Haitian earthquake of 2010 |
| How many people are killed in Haitian earthquake | 160,000 people died |
| What was the mean reason people were injured | 300,000 people estimated to have been injured-mostly from falling debris |
| Liquefaction | Intense shaking causes ground water to mix with mud turning the soil into liquid, structures collaspe.eg kobe japan 5000 deaths |
| Continental-continental | Both continental and light so neither subduct. Both plates buckle and are pushed upward. Mountain ranges are created. E.g Indo-Australian plate and Eurasian plate buckled to create The Himalayas. |
| Epicentre | Directly above the focus, shortest distance to the surface, seismic waves strongest here,most damage caused |
| Seismic Waves | Vibrations from the focus, cause damage in urban areas, Eg. Haiti 2010 |