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95 Cards in this Set
- Front
- Back
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How much water is found in oceans?
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97.4%
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How is fresh water distributed (in percents of earths water volumes)
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2% in ice caps
.6% groundwater .014% lakes rivers and soil moisture |
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Define regalith
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broken up rock
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Define bedrock
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unbroken rock
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what is the zone of saturation?
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pores in rocks which fill up with water. the water table is found here
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what is the water table?
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how high the water comes up towards the surface
in the zone of saturation |
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define unconfined aquifer
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water table can move freely
water table no level since most ground water will move only level if fluid is not moving |
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what are 2 rock properties. define them
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porosity- amount of void space in a rock. ex high=sandstones, limestones, fractured granite low=shales, mudstones
permeability- ability of fluid to move through rock. depends on porosity & connections |
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define aquifer
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porous permeable rock unit that holds ground water. can be confined unconfined and perched. ex edwards aquifer
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Aquitards and Aquacludes
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rock that isn't permeable and contains barriers
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Unconfined Aquifer define
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free water table that follows the shape of the geography. pressure due to depth. ground waters can surface and create marshes. stream disappear into them or be at the water table.
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What does a well do to an unconfined aquifer
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creates a cone of compression and water goes towards bottom of well. changes the water table
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perched aquifer define
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on mt or hill. has impermeable rock layers
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confined aquifer
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top surface sealed in by impermeable rock layer. water can be under high uniform pressure. springs come out of ground from fractures.
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Define karst topography
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geography formed by the under laying bedrock. sink holes and collapse features
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LNAPL define
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light non aqueous phase liquid. like oils, float on waters surface. less dense and relatively insoluble in water
ex. benzene, toluene and xylene |
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DNAPL define
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Dense non aqueous phase liquid. denser than water so it sinks. relatively insoluble.
ex chlorinated solevents, coal tars, tranformer oil. |
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mass wasting define
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downhill movement of soil and rock under the influence of gravity. landslide. classified by what moves how and the speed.
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water in mass wasting
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amount of water varies from wet to dry.
water is usually a trigger |
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angle of repose define
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rock and soil are more stable on slopes with a small angle of repose. water in sm amounts can increase the aor and lg amounts force particles apart decreasing aor
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what are the 4 classes of mass wasting? tell what they entail
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creep-slow
flow-rock or soil moves downhill as a fluid changing its shape fall-rock and soil free falls slide-rock/soil move down-slope as mass along a slide surface |
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types of flows (5)
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rock or debris avalanche
mudflow-wet debris flow-wet earth flow-slow and dry lahar- volcanic mud and debris |
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types of falls (4)
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rock fall
earth fall debris fall talus |
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types of slides (2)
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slides or glides- planar slip surface
Slumps-curved slip surface |
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how do you measure the characteristics of a stream
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by velocity and area
when multiplied you get the discharge (vol of h2o per time) |
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define stream load. what are the three types?
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amount of material carried by a stream.
bed load- on bottom of stream dissolved load- like ca, k, mg suspended load- floating material, most efficient movement, mud easiest to move to gravel hardest |
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define a streams capacity
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total amount of material moved
proportional to discharge |
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define stream competence
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lg suspended material
proportional to velocity |
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what is a graded stream?
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change in slope (called a nix point)
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what do streams adjust to transport the available load in a stream?
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gradient (slope) and velocity
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what is active cutting down in streams
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when a stream tries to reach nirvana with sea level so it cuts down into he earth. has no banks. is fairly straight and there is mass wasting from steep slopes on sides.
ex- grand canyon |
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define sheet flow
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flowing rain water over a lg area
like in a parking lot or thru a field |
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what are the characteristics of a young stream?
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down cutting to achieve ideal longitudinal profile, mass wasting and v-shape
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what are the characteristics of a mature stream?
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meandering (bent), longitudinal profile reached so outward cutting begins, flood plain created, over bank flood deposits, flat bottom valley and steep valley walls at cut bank
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define over bank flood deposits
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floods deposits on the edge of the flood plain
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how do oxbow lakes form
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Chanel begins to bend, water is slower at the bend so deposition occurs until the lake is cut off from the stream
aka meandering scar |
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what happens during flooding
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water leaves the banks, coarse sediment deposited at bank and finer in the middle of stream (natural levee), swamps and marshes form on flood plain edges.
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characteristics of an old age stream
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re cutting flood plain sediments
ex Mississippi flood plain wider than meandering stream, oxbow lakes and meander scars, natural levees |
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characteristics of a rejuvenated stream
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meandering stream begins to down cut when sea level drops or continents rise
ex Colorado plateau of the desert SW |
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define braided stream
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multiple intertwining channels.
stream has more sediment than it can carry most common in desert areas where sporadic flow, and glaciers where washout sed overwhelms vol of melt water |
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define stress
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the force throughout a material.
diff directions in solid and uniform in liquids (pressure). |
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define strain
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deformation of a material from stress
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define elastic material
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will reform to its org shape after deformation from stress
usually these properties under low stress |
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define a plastic material
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permanent deformation of parts of the material from stress
most materials experience this at high stress levels |
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define brittle failure
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when material breaks from stress
usually very large amounts of stress |
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what is elastic strain energy and how is it released?
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the E stored by elastic materials.
when stress is removed or brittle failure occurs (breaks) |
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what is an earthquake?
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the brittle failure of the lithosphere
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why do EQ occur at plate boundaries
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there is a build up of elastic strain E stored from the movement of plates past one another
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how long does strain build up before an EQ and how long does it take to release the E?
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thousands of yrs
minutes |
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what is a fault
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brittle failure of the lithosphere on planar fractures. plates slip past one another
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what is it called if a fault slips without an EQ occurring?
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aseismic slip
plates slide past without catching on each other |
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earthquakes are a function of
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fault size and rupture area
the bigger ^ the bigger the EQ |
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the place where the EQ begins or the fault slips IN the earth is
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the focus
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the place where the EQ begins or the fault slips on the surface is
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the epicenter
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define aftershock
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rupture areas that slip after the initial EQ.
occur in same fault as EQ. usually fall off in intensity can help find where initial break was duration can be months to yrs |
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define seismic waves
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vibrational waves which travel through the earth
waves disturb the material which then tries to obtain its original state |
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what are the 2 types of seismic waves?
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body-travel through earth with min travel time from source to destination.
surface- travel on surface. long wavelengths (L-waves). cause most damage. |
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what are the 2 types of body waves?
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compressional- P waves. travel fastest. disturb vol of material.
shear - disturb material shape. cant travel through liquid. S waves=secondary. |
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what are the 2 types of surface waves?
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rayleigh- LR waves. vertical motion. involve compression
love- horizontal motion. LQ waves. involve only shearing.slightly faster than ^ |
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what do seismographs do?
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record the motion of the ground as a function of time
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what is a seismograph?
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the instrusment that records ground motion as a function of time
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what is a seismometer?
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the device which converts ground motion into electric signals and records them.
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local seismograms are
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distinct p wave arrival followed by a coda-combination of s and surface waves.
may be less than a min |
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distant (teleseismic) seismograms
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show p and s waves at distinct times. p first and most clear. surface waves can ring for hours around the earth.
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what is magnitude?
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the measure of the size of a Eq based on ground motion, measured by a seismograph, and the distance of the seismograph from the epicenter. quantitative in arabic numerals-so can have fractions
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who developed the magnitude method
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richter and gutenburg
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what is duration magnitude?
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the duration of a coda measured for small eq
abreve- Md |
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surface wave magnitude
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abreve- Ms
measures the lg amplitude of surface waves for a 20 sec period |
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body wave magnitude
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used in determining deep eq and explosions like nuclear testing. based on amplitude of p waves
abreve- Mb |
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Moment magnitude
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abreve- Mw
more accurately measures lg eq 7.5+ |
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magnitudes are logarithmic, what does that mean?
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each 1 unit increase in the mag scale is a factor of 10 increase in ground motion. 2 unit change would be 100x
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a whole number increase in magnitude equals a increase in E release
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~30
ex 8.1 is 900 more than a 6.1 |
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avg # of eq ea yr by magnitudes
and total # measured |
>8= 1
7-7.9= 15 6-6.9= 135 5-5.9=1300 4-4.9= 13000 ~30,000/YR |
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what is earth scope?
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am proj of 400 seismometers traveling across country to get info on earths interior and read info from eq around the world
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give ex of lg earth quakes, yr, and their size
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chile 1960 9.5
alaska 1964 9.4 sumatra 2004 9.2 japan 2011 9.1 kamchatka russia 1952 9.0 chile 2010 8.8 |
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where in Am can mega eq occur?
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alaska and pacific NW
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define intensity
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the qualitative damage experienced in a particular location.
in roman numerals so no decimals. |
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what controls intensity of eq?
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magnitude
distance from epicenter direction of movement local bedrock peak ground accecleration |
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why are eq not predictable?
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no reliable precursors
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what is early warning
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since p waves are slower than light, when an eq hits the people furthur away can be warned before the p waves reach them. they can shut off and back up equipment. emergency response can kn ow where to go before it reaches them
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how many barrels of oil per yr do humans consume
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32 billion
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what are the usable sources of E
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solar (geothermal, wind, tides, FF, biofuels)
nuclear |
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how much petroleum does the us consume?
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23%
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what are the forms of FF?
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petroleum- liquid
natural gas coal-solid |
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what is petroleum
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liquid mix of hydrocarbons
single bonded C chains mostly C5-C18 accumulates above source rock peak production 1970 |
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what is a source rock?
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where ff can be extracted from. shales or limestones. partially decayed organic material. dark in color and rotten egg smell.
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how do liquid and gas FF form?
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heated partially decayed org material
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reservoir rock
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porous and permable. top layer of source rock. allows petroleum to come towards sruface
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cap rock
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holds petroleum in so it doesnt surface and go bad. impermeable
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geological trap
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concentrates petroleum
formed by cap rock, reservoir rock and source rock |
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how is nat gas formed?
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heating of part decayed org material (source rock) past petroleum phase.
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characteristics of nat gas
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mostly methane
creates less E than vol releases less Co2 than petroleum peak production 2025 |
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how are nat and shale gas related?
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shale is just still in source rock
extracted via fracing, which may contaminate aquifers |
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how is coal formed?
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dead plants
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characteristics of coal
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hydrocarbon rings
most co2 released peak production 2200 |
