Studied by 118 people
What are three types of deformation of rocks?
Elastically: small stress
Fracturing: vibrations
Plastically: keeps new shape
Can these three types of deformations cause earthquakes?
Earthquakes occur when rocks fracture but DO NOT occur when rocks deform plastically or elastically stretch and snap back into it's original state
What are two movements in earthquakes?
Slippage: minor movement
Fracture: larger movement
What is the focus of an earthquake?
The initial rupture point, where abrupt movement (energy released) creates an earthquake, which typically lies below the surface
What is the epicenter of an earthquake?
The point on Earth’s surface directly above the focus
What are body waves?
Waves that travel through Earth’s interior and carry some of the energy from the focus to the surface
What are two types of body waves?
P waves: travel fast and are the first or “primary” seismic waves to reach an observer
S waves: slower than P waves and thus are the “secondary” waves
What are the characteristics of P waves and S waves?
P waves: fast, compressional elastic wave, same direction in which it propagates; can travel through air, liquid, and solid material.
S waves: waves go up and down, usually travels parallel; can move ONLY through solids
What are surface waves?
Waves that travel slower than body waves; waves that undulate across the ground (ex: waves that ripple across the water when you throw a rock into a calm lake)
What are the two types of surface waves?
Rayleigh waves: waves that move in an up-and-down rolling motion
-Love Waves: waves that move in a side-to-side vibration
What are the characteristics of Rayleigh waves and Love waves?
They are sources of damages
How does a seismograph record seismic waves?
Modern seismographs use a coil fixed to a pendulum that is suspended in a magnetic field. When an earthquake causes the pendulum to move within the magnetic field, it creates an electric current that is amplified and recorded by a computer.
What scales are used to describe the strength of earthquakes?
The Mercalli scale
The Richter scale
The Moment magnitude
How does the Mercalli scale describe earthquake strength?
Earthquake strength is based on structural damage
(ex. an earthquake that destroyed many buildings was rated as more intense than one that destroyed only a few).
How does the Richter scale describe earthquake strength?
Earthquake strength is described by the amount of energy that is released during an earthquake (measures energy by the height of the largest wave)
How does the moment magnitude describe earthquake strength?
Earthquake strength is described by the surface area of fault movement, the offset produced on the fault, and a measure of rock strength are multiplied together; moment magnitude scale (measures energy as a function of movement and fault surface area)
How can we locate earthquakes?
By determining the distance from a recording station to both the epicenter and the focus of an earthquake
If a seismograph happens to be close to an earthquake epicenter, the different waves (P waves and S waves) will arrive in rapid succession
If a seismograph is located far from the epicenter, the S waves arrive after the P waves arrive, and the surface waves are even farther behind.
The TIME-TRAVEL CURVE is used to calculate the distance between an earthquake epicenter and a seismograph.
Where do most earthquakes occur?
Along plate boundaries, where tectonic plates diverge, converge, or slip past one another
Which plate’s boundary can cause significant earthquakes?
Transform plate boundary in the San Andreas Fault Zone
How rocks and soil influence damages in an earthquake?
Bedrock vibrates during an earthquake, and buildings may fail if the motion is violent enough. However, most bedrock returns to its original shape when the earthquake is over, so if structures can withstand the shaking, they will survive
Bedrock is a good foundation for an earthquake-prone area
Structures are usually built on sand, silt, or clay. Sandy sediment and soil commonly settle during an earthquake. This displacement tilts buildings, breaks pipelines and roadways, and fractures dams
What are some other factors of damage in an earthquake OTHER THAN rock and soil?
Soil type, distance from epicenter, quality of construction (withstand shaking and fire)
How is tsunami formed in an earthquake?
When an earthquake occurs beneath the sea, part of the seafloor rises or falls. Water is displaced in response to the seafloor movement, forming a wave or series of waves. Sea waves produced by an earthquake are often called tidal waves, but they have nothing to do with tides
What is difference of long-term prediction and short-term prediction?
Long-term prediction: recognizes that earthquakes have recurred many times along existing faults and will probably occur in these same regions again; tells us where earthquakes are likely to occur. This information is useful because it allows engineers to establish strict building codes in earthquake-prone regions
Short-term prediction: forecasts that an earthquake may occur at a specific place and time. Short-term prediction depends on signals that immediately precede an earthquake; Foreshocks are small earthquakes that precede a large quake by a few seconds to a few weeks
What phenomena can help to predict an earthquake?
If you live above the plate boundary
What is fresh water?
Water that is relatively pure, with few dissolved salts
How much water on Earth is freshwater (%)?
Only 2.5%
How is freshwater distributed on earth? (Give the percentage in ice, ground, surface from largest to smallest amount)
Ice caps/Glaciers = 1.8%
Groundwater = 0.63%
Lakes/Rivers = 0.01%
Atmosphere = 0.001%
How is water stored in different spheres?
There is a continuous circulation of water among the four spheres due to the hydrologic cycle, or better known as the water cycle?
What are the main processes that control the water cycle?
Evaporation: Water evaporates from the continents and oceans to form water vapor in the atmosphere.
Condensation: This vapor eventually condenses and falls back to the surface as rain or snow.
Precipitation: Most precipitation lands on the ocean, partly because it covers most of the planet. It sinks into the ground or runs off into rivers to form lakes or enter oceans, warming
How does water transport into different spheres?
Through a number of different processes:
Evaporation: moves water from water bodies into atmosphere
Precipitation: sinks into the ground or runs off into rivers to form lakes or enter oceans
Transpiration: water evaporates directly from plants
Infiltration: water seeps into the ground
Explain the water cycle
Water evaporates from the continents and oceans to form water vapor in the atmosphere. This vapor eventually condenses and falls back to the surface as rain or snow. Most precipitation lands on the ocean, partly because it covers most of the planet.
What are perennial streams?
Streams that are in temperate climates that usually run year round even during times of drought, because they are fed by groundwater that seeps into the streambed
What are intermittent streams?
Streams in arid environments that flow only when water is provided by a precipitation event.
What factors influence the stream velocity and the discharge rate?
The velocity of its water increases when its discharge increases. -> Thus, a stream flows faster during flood -> A stream’s discharge can change dramatically from month to month or even during a single day depending on what season we happen to be in (early summer or dry season)
How channel characteristics impact the velocity?
-> Friction between flowing water and the stream channel slows current velocity. -> Consequently, water flows more slowly near the banks than near the center of a stream. -> Deep and narrow flows faster than a broad and shallow. Straight flows faster than with lots of curves
How to calculate velocity and discharge rate?
Discharge rate (volumetric flow rate)(Q): the volume of fluid which passes per unit time = volume of water/time (ft.^3/s) = area (A) * velocity (V)
Flow rate and velocity are related by Q=A¯v where A is the cross-sectional area of the flow and v is its average velocity.
What is meander?
A series of twisting curves or loops in the course of a low-gradient stream
What is Point bar?
A deposit of sediment in the slower water on the inside of a meander.
What is Oxbow lake?
A crescent-shaped lake created where a meander loop is cut off from a stream and the ends of the meander become plugged with sediment
What are braided streams?
A stream that flows in many shallow, interconnecting channels that are usually separated by emergent sediment bars
How are all of these components of a stream (meander, point bar, oxbow lake, braided streams) formed?
Meander: formed by lateral erosion
Point bar: formed by water piling up against the outside bank causes the flow around the inner bank to be both shallower and slower and promotes the deposition of sediment there
Oxbow lake: formed where a meander loop is cut off
Braided streams: formed because the stream’s capacity has been exceeded by its sediment supply
What is the drainage basin?
The region that is drained by a single stream
An area of land that feeds into a river or stream
Contiguous land that is all “downhill”
What is the largest drainage basin in the U.S?
The Mississippi-Missouri drainage basin
What is a delta and it's distributaries?
-Delta: A fan-shaped accumulation of sediment formed where a stream enters a lake or ocean; deposition into aqueous environment
Distributaries: fan of water channels in a delta
What are the different sections of a delta?
Delta top: The upper surface of a delta, including the parts above and below water
Delta front: The more steeply sloping, usually submerged, outer edge of a delta beyond the delta top
Prodelta: The fine-grained, outermost edge of a delta, located offshore beyond the delta front
Why is a delta important?
Because they provide important nursery grounds for many fish species, and support both subsistence and commercial fisheries due to their nutrient-rich sediments that are deposited in it during floods. They're also prime places for people to settle.
What are flood plains?
That portion of a river valley adjacent to the channel; it is built upward by sediment deposited during floods and is covered by water during a flood
How lakes formed in different conditions?
Lakes can be formed by sediment dams which come from the glaciers that have melted
Kettle lakes: lakes caused initially by blocks of remnant glacial ice; A lake that forms in a depression created by a receding glacier, filled with the water from the melting glacier.
What is an oligotrophic lake?
A deep lake characterized by nearly pure water but with low concentrations of nutrients, thus sustaining relatively few living organisms.
What is an eutrophic lake?
A relatively shallow lake characterized by abundant nutrients, thus sustaining multiple living organisms
Explain the cause-effects chain of eutrophication
Eutrophication sets off a chain reaction in the ecosystem, starting with an overabundance of algae and plants. The excess algae and plant matter eventually decompose, producing large amounts of carbon dioxide. This lowers the pH of seawater, a process known as ocean acidification. Acidification slows the growth of fish and shellfish and can prevent shell formation in bivalve mollusks. This leads to a reduced catch for commercial and recreational fisheries, meaning smaller harvests and more expensive seafood.
What are wetlands?
Regions that are water soaked or flooded for all or part of the year; includes swamps, bogs, marshes, sloughs, mudflats, and floodplains.
What are the three types of wetlands?
Swamps- woody plant and Tree
Bogs – cold areas
Marshes- grass plant
Name the functions of wetland
Biologically productive
Degrade pollutants
Mitigate flooding
Carbon storage
Habitat
Why are wetlands disappearing?
Wetlands have been lost or degraded by both humans and natural causes.
Many wetlands have been drained, or their sources of water cut off, through the construction of dams or dikes.
Others have been filled, logged, or mined, while the introduction of nonnative invasive species or toxic levels of pollution or nutrients continues to cause widespread wetland degradation.
Natural wetland loss can occur by subsidence, sea level rise, drought, and erosion by large storms.
What are the water table and aquifers?
Water table: The top surface of the zone of saturation; the water table separates this zone from the zone of aeration above
Aquifer: A body of rock or soil that can yield economically significant quantities of groundwater; should be both porous and permeable.
What is the confined aquifer and non-confined aquifers?
Confined aquifer: An inclined aquifer sandwiched between layers of impermeable rock; typically, the water in the lower part of the aquifer is under pressure from the weight of water above
Non-confined aquifer: where the rock is directly open at the surface of the ground and groundwater is directly recharged, for example by rainfall or snow melt; not confined by impermeable material
How is the artesian well is formed?
It is formed when a well is drilled into a confined aquifer, in which the water rises without pumping and in some cases flows to the surface
Definition of withdrawal water
Any process that uses water and then returns it to Earth locally
Definition of consumptive water use
Any process that uses water and then returns it to Earth far from its source
Definition of non consumptive water use
Water that has been used but can be recycled and reused and leads to no diminishment in it's original source
What are the differences between consumptive and non consumptive water use?
Water used consumptively diminishes the source and is not available for other uses, the water does not return directly back to it's source
Non consumptive water use does not diminish the source or impair future water use, and will be returned locally
What are the major industries that contribute to water use?
Industry = sometimes by power plant
Agriculture = irrigation
What are the three water usage categories?
Domestic
Industrial
Agricultural
How is water withdrawn and consumed in different categories in the U.S.?
Domestic: The average American household uses about 1100 liters (300 gallons) per day—many times the amount needed to maintain a healthy life (used when taking a shower or flushing a toilet usually withdrawal non consumptive)
Industrial: The cooling systems in electric power-generating plants (run by fossil fuels or nuclear power) account for roughly 45 percent used each day in the United States; (withdrawal/non consumptive since it is returned to it's source)
Agricultural: Agriculture accounted for 32.5 percent of total water use in the United States and 76 percent of all fresh groundwater withdrawals -> roughly 70 percent of all global water consumption is used to irrigate crops (very consumptive)
What are surface water diversion systems?
A pipe, canal, or other infrastructure that transports water from its natural place and path in the hydrologic cycle to a new place and path to serve human needs
What problems are associated with dams?
Water loss
Salinization
Silting
Erosion
What are the advantages and disadvantages of dams?
Advantages: to be used for power, flood control, increased water availability in many regions and produced large amounts of hydroelectric energy
Disadvantages: Dams can fail and flood landscapes; there are recreational and aesthetic impacts, there are ecological disruptions, and lots of people often have to move to accommodate dam projects
What is ground water depletion?
The use of water faster than it is replenished
What are the effects of groundwater depletion?
Cone of depression: deflection of water table caused by over-pumping
The water table can fall
What is land subsidence?
The irreversible sinking or settling of Earth’s surface
Caused by the excessive removal of groundwater or loss of aquifer porosity
What is saltwater intrusion?
Depletion of fresh ground water in coastal zones allows salty groundwater to intrude an aquifer
What is regulated in the Clean water Act of 1972?
The cleaning of the nation’s rivers, lakes, and wetlands and forbidding the discharge of pollutants into waterways.
What are the various water pollutants introduced in the class?
Biodegradable pollutants:
Sewage: (food/human waste, detergent soap)
Disease organisms
Phosphates and nitrate fertilizers
〖𝐵𝑂𝐷〗_5 (biological oxygen demand)
Nonbiodegradable pollutants:
PBTs – nonbiodegradable poisons
Organic industrial compounds: (some pesticides, mine waste, sediment)
Toxic organics (mine wastes, road sale, lead)
Mineral sediments
What are the sources for those water pollutants?
Point sources:
Sewage treatment plants
Water treatment plants
Factories
Non point sources:
City streets
Croplands
Animal feed lots
What is point source pollution?
Stems from specific site (septic tank, gas spill) and you are able to determine where the pollution has come from
What is non point source pollution?
stems from a broader area (fertilizer, pesticide runoff from lawns/farms); which makes it harder to determine exactly where the pollutants came from
Provide different pollution sources based on two concepts
Point sources: Water treatment plants and factories (spill from a septic tank)
Non point sources: Rural homes, croplands, and animal feedlots (fertilizer spread over a lot)
The boundary in the mantle where composition changes allows seismic wave velocities to do what because pressure is great enough that the minerals in the mantle recrystallize to form denser minerals such as peridotite is called the 660-kilometer discontinuity
a. None of the above b. Velocity decreases c. Velocity increases d. Velocity remains the same
Velocity increases
The Mohorovicic discontinuity was identified through the passage of seismic waves between the ____ and the ____?
a. inner core; outer core b. upper mantle; lower mantle c. crust; mantle d. mantle; core
Crust; mantle
Which specific type of body wave travels through the Earth’s inner core indicating it is a solid rather than liquid in composition ?
a. P waves b. Raleigh waves c. S waves d. Love waves
P waves
P, or primary, waves ____
a. move along Earth's surface only b. pass through liquids only c. are the slowest waves generated by an earthquake d. are characterized by alternate compression and expansion of rock
Are characterized by alternate compression and expansion of rock
The San Andreas Fault zone is an example of a(n) ____
a. earthquake zone at a subduction plate boundary b. Benioff zone c. earthquake zone at a divergent plate boundary d. earthquake zone at a transform plate boundary
earthquake zone at a transform plate boundary
S, or shear, waves ____
a. move through solids, liquids, and gases b. move along Earth's surface only c. are faster than P waves d. vibrate perpendicular to the direction they travel
vibrate perpendicular to the direction they travel
Rock deforms ____ under small amounts of stress and returns to its original shape and size when the stress is removed such as folds
a. seismically b. plastically c. fracturally d. elastically
elastically
A rock that has deformed ____ under stress keeps its new shape when the stress is released
a. flexibly b. plastically c. elastically d. non permanently
Plastically
When stressed by a tectonic force, rock stores elastic energy that causes deformation, or ____, to build
a. fractures b. vibrations c. strain d. compression
strain
Modern seismologists typically use which scale to most accurately assess the total amount of energy released in an earthquake? __________________
a. Moment magnitude b. Mercalli Scale c. Richter Scale d. Benioff Scale
Richter Scale
The water on the outside of the bend of a stream meander moves ____
a. slower than the water on the inside b. mostly upward in a process called upwelling c. faster than the water on the inside d. the same speed as the water on the inside
faster than the water on the inside
A stream’s ____ is the volume of water flowing downstream over a given period of time
a. sinuosity b. discharge c. gradient d. capacity
discharge
____ is the volume percentage of open spaces within a rock or soil
a. Porosity b. Recharge c. Turnover d. Permeability
Porosity
Levees may solve flooding problems in the short term but they can cause larger and more destructive floods over the long term
True or False?
True
If fish on lake in your area is nutrient-poor lake, it would be low in biodiversity because it is what specific type of lake?
a. Well-nourished b. Oligotrophic c. Eutrophic d. Minitrophic
Oligotrophic
Humans use freshwater that accounts for what specific percentage of all of the water on Earth?
a. 1.0% b. 97.5% c. 1.8% d. 0.64%
0.64%
Most of Earth’s freshwater (in liquid, frozen, or gas form) is contained in ____.
a. the atmosphere b. groundwater c. ice sheets and glaciers d. lakes
ice sheets and glaciers
A geologist would expect an unconfined aquifer to rise above the water table during extremely wet years.
True or False?
True
Caverns form the dissolution of ________ because rainwater reacts with atmospheric carbon dioxide to become slightly acidic.
a. granite b. igneous bedrock c. limestone d. conglomerate
limestone
The ____ of a stream is a measure of the largest particle it can carry.
a. capacity b. competence c. gradient d. discharge
competence
A(n) ____ forms when a meander loop is cut off and isolated from a stream.
a. kettle lake b. crater lake c. delta d. oxbow lake
oxbow lake
Which is not a true statement about eutrophic lakes?
a. Generally has high productivity b. Is generally very deep c. Has a high nutrient supply d. Is also referred to as a well-nourished lake
Is generally very deep
Note 
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