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37 Cards in this Set
- Front
- Back
Define an earthquake |
a vibration of the ground |
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elastic rebound theory |
if stress is applied to rock, rock undergoes elastic deformation. if enough stress is applied, rock ruptures and energy is released as earthquake vibrations and rock returns to original non stressful state.
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list the types of seismic waves |
Primary (p) wave, Secondary (S) wave, Surface Wave |
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how are earthquakes measured |
mercalli scale, richter scale, moment magnitude scale |
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name various ways that earthquakes can cause damage on the surface of the earth |
ground shaking, landslides, liquefaction, fires, tsunamis |
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name the 4 primary layers of the earth |
crust, mantle, outercore, innercore |
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secondary layers of the earth |
lithosphere- surface (100 km), solid, rigid and brittle asthenosphere- 100 km-700 km, weak, plastic, gooey, capable of flow |
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describe the theory of plate tectonics |
Pangea- supercontinent, continental drift by alfred wegener |
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three types of plate boundaries |
divergent, convergent, and transform |
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name the geographical locations where the plate boundaries are located |
divergent- mid atlantic ridge, mid indian ridge, east pacific rise
convergent- cascade mountains, andes mountains transform- san Andreas fault, pakistan |
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Primary (P) Wave |
type of seismic wave, propagates via compression and expansion, travels 16000 mph, can travel through all mediums
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Secondary (S) Wave |
types of seismic wave, propagates via shearing motion, travels 10,000 mph, only travels through solids |
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Surface Wave |
type of seismic wave, propagates similar to an S wave, slowest (few 1000 mph), causes most damage |
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Mercalli Scale |
based on amount of damage the earthquake caused, ranges from I to XII
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Richter Scale |
based on amplitude of seismic wave, ranges from 1 to 10. logarithmic scale- for every unit on the scale, intensity increases by 10X, energy increases by 30X, poorly assesses large EQ's |
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Moment Magnitude Scale |
based on amount of displacement along fault, most accurate to date, best estimates intensity of large EQ's, best estimates energy released, verified in the field |
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Crust |
outermost, thinnest, two types: continental crust and oceanic crust continental- up to 70 km composed of felsic oceanic- 5-6 km thick, composed of mafic igneous rock (basalt) |
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Mantle |
2900 km thick, composed of peridotite (ultra mafic) |
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Outercore |
2300 km thick, composed of iron, believed to be liquid |
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innercore |
1200 km radius, solid very dense, composed of iron and nickel |
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hot spot |
weak zone in the crust that allows magma to reach the surface (example: hawaii) |
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paleomagnetic evidence of plate tectonics |
magnetic reversals- show flip flopping of earth's magnetic field and supports divergent plate activity |
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driving mechanism for plate tectonics |
convection- migration of warm material into cool material |
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features of a volcano |
mountain formed by extrusion of molten rock, lava |
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types of material expelled during volcanic eruptions |
pyroclastic material- broken rock fragments classified by size: ash (smallest), lapilli (walnut size), blocks/bombs (largest) |
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three types of volcanoes |
1.shield: largest, gently sloping slides, composed of basaltic lava 2. stratovolcano: moderate size, moderately sloping sides, composed of pyroclastics and lava 3. cinder cone: smallest, steep sides, composed of pyroclastics |
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features associated with volcanic activity |
caldera- large depression formed by a collapsed volcano volcanic neck- erosional remnant of a former volcano |
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major water bodies on the surface of the earth |
pacific ocean, atlantic ocean, indian ocean, arctic ocean, southern ocean |
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pacific ocean |
largest ocean, largest geographical feature on earth, 13,000 ft avg |
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atlantic ocean |
about half the size of the pacific, bounded by almost parallel continent, 12000 ft |
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indian ocean |
slightly smaller than atlantic but has roughly same average ft, mostly in southern hemisphere |
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arctic ocean |
only 7% the size of the pacific, 2500 ft avg |
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southern ocean |
found below 50 degrees south parallel, encircles antarctica, distinguished by changes in temp, salinity and fauna |
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active continental margin |
associated with plate boundary, EQ's and volcanoes, narrow band of highly disturbed sediment |
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passive continental margin |
not associated with a plate boundary, little to not EQ's and volcanoes, thick wedge of undisturbed sediment. flat slope |
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mid ocean ridge |
represent areas of divergence 46000 miles, high compared to rest of ocean floor (volcanic activity pushes surface upward) |
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sea floor sediments |
terrigeneous, biogeneous, hydrogenous, oil and natural gas, gas hydrates, sand and gravel, manganese nodules |