Term
| WHAT CAUSES AN EARTHQUAKE ? |
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Definition
| VIBRATIONS OF EARTH PRODUCED BY THE SUDDEN RELEASE OF ENERGY |
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Term
| describe the location of an epicenter and focus |
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Definition
Epicenter is the location on the surface of Earth directly above the focus
Focus is the point within the Earth where the earthquake starts |
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Term
| What is elastic rebound hypothesis ? How does it relate to earthquakes ? |
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Definition
| Elastic rebound hypothesis is the release of built up energy.Most earthquakes are produced by the release of elastic energy stored in rocks that has been subjected to great focus |
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Term
| Describe aftershocks and foreshocks ? |
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Definition
Aftershocks are small quakes that come after a major earthquake
Foreshocks are small quakes that come before a major earthquake |
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Term
| How are earthquakes measured ? |
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Definition
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Term
| Describe surface, S waves, and P waves |
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Definition
Surface waves-seismic waves that travel along Earths outer layer moves up and down,and side to side
S waves-shake particles at right angles to their direction of travel,slower than P waves but faster than S waves
P waves-they push(compress),and pull(expand) rocks in the direction the waves travel |
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Term
| How do scientist locate earthquakes ? (distance and directions) |
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Definition
| The difference in velocities of P waves provides a way to locate the epicenter.Scientists use a travel time graph in which one needs at least 3 seismograph station data |
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Term
| Where do most earthquakes occur ? |
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Definition
| Around the edge of the Pacific Ocean |
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Term
| Describe each of the different scales used to measure earthquakes.Which one measure intensity and which one measures magnitude of an earthquake. |
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Definition
Richter scale-measures the magnitude of an earthquake.Based on the amplitude of the largest seismic wave.
Intensity-is a measure of the amount of earthquake shaking at a given location based on the damage
Magnitude-is a measure of the size of seismic waves or the amount of energy released at the source of an earthquake |
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Term
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Definition
| Stable soil turns into a liquid that is not able to support buildings or other structures |
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Term
| What causes tsunamis ? What warning system is used ? |
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Definition
| A tsunami is called a seismic sea wave.A tsunami is triggered by an earthquake.It occurs where a slab of ocean floor is displaced vertically along a fault.Scientist use water levels in tidal qauges to determine if a tsunami is forming |
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Term
| What are some other dangers that can occur due to earthquakes ? |
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Definition
| Landslides and ground subsidence or the sinking of the ground triggered by the vibration occurs,many houses are destroyed,and fires are caused when gas and electrical lines are cut |
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Term
| Describe the three layers of crust ? |
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Definition
Crust- lithosprere,consists of the crust and the uppermost mantle,it is cool and rigid shell,100 km thick
Mantle- asthenosphere,soft and a weak layer,below the lithosphere,rocks are close to melting
Outer core- is liquid and 2260 km thick,metallic iron and generates the Earths magnetic field
Inner core- solid layer having a radius of 1220 km thick,has high temperature and high pressure,made mostly of nickel |
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Term
| Describe continental drift ? |
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Definition
| The continental drift hypothesis stated that the continents had once been joined together to form a single supercontinent |
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Term
| Who came up with the idea of continental drift ? |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| What kind of evidence is present to verify the idea of continental drift ? |
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Definition
| shorelines look like they fit together,fossils organisms found on different land masses,mountain belts end at one coastline only reappear on landmasses across the ocean,ancient climates |
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Term
| What are plate tectonics ? |
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Definition
| According to plate tectonics theory the uppermost mantle,along with the overlying crust,behaves as a strong rigid layer |
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Term
| How many plates are there ? Name each. |
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Definition
There are 7 major plates and 6 minor plates.The largest is the Pacific plate which covers most of the pacific ocean
North american
south american
pacific
african
eurasian
australin-indian
antartic
carribean
nazca
phillipine
arabian
cocos
scotia |
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Term
| What happens to plate boundaries ? |
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Definition
| The grinding movements of Earths lithosphere plates generate earthquakes,create volcanoes,and deform large masses of rock into mountains |
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Term
| Describe each of the boundaries and tell what is happening at each. |
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Definition
Divergent boundaries occur when two plates move apart.This process results in upwelling of material from the mantle to create a new seafloor
Convergent-The result is a collision between two continents,which cause the formation of complex mountains such as the Himalayas in SOuth america
Ocean-when two oceanic slabs coverage one descends beneath the other,causes volcanic activity
Transform-transform fault boundaries are margins where two plates grind past eachother without the production or destruction of lithosphere |
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Term
| What is the driving force of the plate tectonics ? |
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Definition
| Convection occurring in the mantle is the basic driving force for the plate movement |
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Term
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Definition
| A concentration of heat in the mantle capable of producing magma,which rises to Earths surface |
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Term
| What are some evidence of plate tectonics ? |
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Definition
Paleomagnetism
Earthquake patterns
Ocean drifting
Hot spots |
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