Term
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Definition
*WIND
-strong wind and long "fetch" have larger waves |
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Term
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Definition
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Term
| longshore current/transport |
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Definition
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Term
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Definition
| gravitation interaction among Earth, moon, sun and oceans |
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Term
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Definition
sun, moon, and earth line up
-higher high tides and lower low tides |
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Term
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Definition
sun,earth, and moon form right angle (moon is above the earth)
-lower high tides, higher low tides |
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Term
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Definition
*magnify effects of tides, waves, etc
*normal part of beach evolution |
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Term
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Definition
*formation of a beach
*a natural beach is not destroyed by "beach erosion"
*Beach is lost only when structures are employed to lock the shoreline in place |
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Term
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Definition
*action of waves on shoreline- removal of all but coarsest sediment (SAND)
*as shoreline moves, beach moves with it |
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Term
| causes of shoreline retreat |
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Definition
*global sea-level rise
*land subsidence
*sand starvation |
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Term
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Definition
*present rate: 2mm per year and four feet of lateral shoreline movement
*10-25 cm over a century |
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Term
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Definition
*examples- east texas and lousiana
*Louisiana losing 25 mi^2 of land per year |
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Term
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Definition
*hard stabalization
*soft stabalization
*move out of the way |
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Term
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Definition
*build hard, immovable structure to anchor beach
*structures are seawall and groin/jetty |
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Term
| soft stabalization (beach replenishment) |
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Definition
*add sand to beach
*advantages-save beach and buildings
*disadvantages-expensive and has a short lifespan |
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Term
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Definition
*stress
*strain
*britle deformation
*ductile deformation
*fault
*joint
*strike and dip
*dip
*strike |
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Term
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Definition
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Term
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Definition
| response of rock to stress |
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Term
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Definition
| breakable, faulting (rock breaks) |
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Term
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Definition
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Term
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Definition
| a break in a rock along movement |
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Term
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Definition
| a break in a rock along NO movement |
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Term
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Definition
| describes the orientation of a planier feature (could be tilted, folded rock layers) |
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Term
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Definition
| tells you the downward tilt of a feature; measured as an angle below horizontal |
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Term
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Definition
| compass direction of the intersection of a tilted plane with the horizontal |
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Term
| ductile deformation again |
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Definition
*(folds)
*anticline- "A" up rock layers
*synticline- "U" shaped rock layers
*folds result from compression/shortening |
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Term
| brittle deformation again |
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Definition
*(faulting)
*dip/slip faults-motion parallel to the dip direction, has both vertical and horizontal movement |
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Term
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Definition
*volcanic eruptions
*nuclear weapons testing
*elastic rebound |
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Term
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Definition
*rocks bend elastically as stress applied
*faulting releases elastic strain instantly
*earthquake waves radiate out from fault break
*aftershocks as fault strain fully dissipater |
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Term
| magnitude and intensity- scale (1902) |
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Definition
*subjective
*based on eyewitnesses accounts, damage
1-barely felt
6-felt by all, slight damage
12-total destruction |
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Term
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Definition
m=log10(X/T)+lamda
*m-magnitude
*X-amplitude of ground motion
*T-period of ground motion
*lamda-distance correction function
*m=6-7:serious
*m=7-8:major
*m=8-9:massive |
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Term
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Definition
*similar to richter scale
*more accurate and consistent
*based on: physical prop of affected rock, surface area of fault rupture, amount of fault slip |
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Term
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Definition
| *point of earth's surface is vertically straight above the focus(earthquake) |
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Definition
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Term
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Definition
| weight that shows motion of disturbance within the earth |
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Definition
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Definition
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Term
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Definition
*secondary waves
*shear waves
*motion within wave is perpindicular to direction of travel
*travel through solid only |
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Term
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Definition
*analogues to waves on water surface
*propogate along free surface
*circular ground motion (groud-roll) |
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Term
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Definition
*almost impossible to make precise predictions
*uncertainties of decades to centuries
*earthquake precursors
*"seismic gap" method |
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Definition
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Definition
*tilting or swelling of ground
*groundwater pressure change
*electromagnetic field changes
*animal behavior |
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Definition
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Term
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Definition
| paper with pen that shows the disturbance of the earthquake |
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Term
| damage control of earthquakes |
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Definition
*build flexible structures, anchor structures to bedrock
*no heavy roofs
*problems with soft sediments
*Loma Prieta-earthquake
*no heavy roofs |
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Term
| problems with soft sediments |
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Definition
*liquification-(anchorage,ak) sed. liquifies
*amplification (oakland, ca) sed is weaker, movement (Loma Prieta) |
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Term
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Definition
*(tidal waves)
*off shore earthquakes create waves in the sea
*waves propogate out of the epicenter
*can be huge when hit land |
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Term
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Definition
*abrupt jump to high velocity material several km deep
*deeper earthquake waves travel faster than shallow
*we can infer that the crust is underlain by denser mantle |
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Term
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Definition
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Term
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Definition
*earth behaves like a giant magnet
*earths interior too hot to contain magnetic minerals
*field most likely generated by rotation of solid inner core within liquid core |
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Term
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Definition
*polarity of earths magnetic field spontaneously reverses
*intervals of a few 10000 years to millions of year (avg-250000yrs)
*last reversal=780000 years ago
*reversals recorded in minerals that act as natural compasses, esp iron rich igneous minerals |
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Term
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Definition
*1908-1912: alfred wegener-proposed hypothesis of cont drift
*1950s-1960s=mapping of ocean floor, leads to theory of plate tectonics |
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Term
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Definition
| *cont drift- all of the continuity fit together like a jigsaw puzzle; |
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Term
| evidence of plate tectonics |
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Definition
*distribution of fossils
*paleo climate info=ancient climate
*united glaciacion=combine all continents into antarctica |
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Term
| important steps to theory |
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Definition
*look at sea floor
*poor resolution of earthquakes
*evidence of sea floor (structure, age, magnetic) |
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Term
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Definition
| *polar wandering, heat flow, realtime |
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Term
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Definition
*mid ocean ridge (block faulting) normal fault-ridge being pulled apart
*large mtn chain
*intense volcanic activity
*seafloor spreading @ ridge= crustal expansion apart |
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Term
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Definition
*not older than 180 million years
*covered by sed. layers
*youngest sea floor coincides with mid ocean ridge |
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Term
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Definition
*theory of plate tectonics- earths lithosphere divided into discrete plates that are in motion relative to each other
*interactions between plates are the main cause of volcanism, earthquakes, mtn bldg and other geo phenom
*plate motion is driven by thermal convection in the mantle |
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Term
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Definition
| plates pull apart, gap filled with lava, build new ocean crust |
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Term
| locations of divergent boundaries |
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Definition
*midocean ridges (most)
*cont drift (a few) -ocean floor=basalt |
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Term
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Definition
located in the eastern part of africa
*linear drift-red sea and gulf of aden |
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Term
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Definition
| *plates ram together, subduction zone, ocean trench, volcanoes, ocean crust destroyed |
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Term
| types of convergent boundaries |
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Definition
| *oceanic/cont and oceanic/oceanic, cont collision. west side of pacific is oceanic convergent, east side= cont drift, himalaya=cont collision |
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Term
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Definition
*(san andres fault, ca)
*plates slide horizontal
*links segments of divided boundaries, earthquake hazards |
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Term
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Definition
| *earth is dynamic, constant crustal motion, and crustal deformation, thermal uplift (fault) |
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Term
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Definition
*isostacy- earths crust floats on top of mantle, lighter cont. crust floats higher, thicker cont. crust floats higher
*thermal effects- hot mantle may up crust, important at mid ocean |
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Term
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Definition
| assertion of earths lower atmosphere and oceans have warmed during past |
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Term
| metereological phenomenon |
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Definition
*climatical evidence clearly tells us the earth is warmer now than it was 10 years ago, 50 years ago, 100 yrs ago, or 10000 yrs ago
*causes of climate change poorly understood |
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Term
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Definition
*some argue that the earth is warmer bc of human activities and that therefore we need to change our ways
*others argue- the earth isnt warmer, observed warming is natural |
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Term
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Definition
*complex balance of forces
*atmospheric- circulation patterns, greenhouse gasses
*oceanic-circular patterns, greenhouse gas source/sink
*geological-position of continents, volcanic gasses/dust
*astronomical (orbital) |
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Term
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Definition
*as atmospheric, oceanic, geological, and astronomical change, earth's climate changes
*earths climate has changed dramatically during the very recent geologic past |
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Term
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Definition
| entrapment of heat by certain atmospheric gasses(greenhouse gasses) |
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Term
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Definition
| *glasses that are transparent to sunlight but trap heat (infra-red) energy (H2o,CO2,CH4,others) |
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Term
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Definition
*sunlight (light energy)-passes through atmosphere,absorbed by ground, ground warms up
*heat energy from ground radiated back into atmospheric
*heat absorbed by greenhouse gasses
*atmosphere warms up |
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Term
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Definition
*normal part of earths climate
*keeps eart 60 degrees
*without= 15 degrees |
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Term
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Definition
*ice cores
*tree rings
*lake and ocean sediment
*cave sediment |
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Term
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Definition
*greenland and antarctica
*trapped atmospheric gasses
*snow depth
*dust, contamination |
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Term
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Definition
Pleistocene era (1.65 my-10K yrs ago)
*numerous advances and retreats of continental glaciers in northern hemisphere |
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Term
| most important of measuring past temps |
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Definition
*ice cores
*ocean sediment |
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