GEOL 101 Final
the iowa daily erosion project and research by iowa state agronomists suggests that
iowa is losing soil at a rate thats much grater than the rate of formation of new soil
the water table
is the boundary between the unsaturated zone and the saturated zone
W x D x V
Big rivers have large discharges. Little streams have little discharges even if they are moving fast.
Seismic Waves
Body waves, surface waves.
How is Richter magnitude determined?
The difference between 1 and 2 is 10x.
Stage height
The height of a river surface itself.
What is a strike?
Intersect of layer with horizontal-amakes line
Brittle Deformation - Joints
Joint is a fracture with no movement
What is shear stress? What do you get?
Lateral movement side to side. It gives us strike slip faults
Effects of Earthquakes
Liquefaction, landslides, tsunami, material amplification
Strike Slip Faults- shear
"Movement along the fault is horizontal. Dip of fault plane is vertical. Can be right lateral or left lateral. Side to side movement.
Brittle vs. Ductile Deformation
Ductile is Compressional Stress
Discharge
Volume of water per given time (cfs). Increases down stream. Changes over time.
which of the statements about groundwater pollution is correct?
as the contaminant plume moves away from the contaminant source, the pollutants decrease in concentration, but the area will get wider
what can happen if excessive nutrients run off in to a lake
algae blooms may develop, and when the algae dies and decomposes, dissolved oxygen in the water will be consumed
mine tailings
all of the above
sediment pollution
all of the above
to prepare a landslide hazard map for an area, you would ideally need to know something about
all of the above
what are the causes of shoreline erosion
all of the above
which of the following are methods used to reduce soil erosion in agricultural land
all of the above
how does water influence slope stability?
all the above
what are some of the reasons why land subsidence occurs?
all the above
the water resources in the colorado river basin
are stressed due to ongoing drought and continued population growth in this region
what are the following statements describing
bauxite processing
soil erosion in the loess soils in western Iowa
both a and b
the city of des moines gets its drinking water from the raccoon river and shallow groundwater recharged by the river. elevated nitrate levels in this water
both a and b
why did flint michigan have problems with lead in their water
both a and b
groundwater withdrawal
both a and c
which soil holds on to the most water and why
clay soil because pore spaces are very small and the clay surfaces are electrically charged
Reverse and thrust faults
compression. Hanging wall block moves up relative to the footwall block
how does soil erosion affect soil fertility
fertility is decreased due to the preferential loss of lighter clay and organic particles
how do falls and flows differ?
flows contain material mixed with water and move downslope like a fluid and falls involve the free fall of rock from a cliff face
which of the following statments about cation exchange in soils is CORRECT?
plant roots exchange hydrogen cations for cations such as potassium, calcium, that are attached to the surface of both clay particles and organic matter
which of the following statements about rare earth elements is CORRECT
rare earth elements are critical materials that are used in green energy technology, consumer electronics, and military applications
Seismographs
record seismic waves by producing a seismogram
Dip slip Faults
reverse of normal. Have up and down motion. Hanging wall and footwall. Diagonally upward always. Points to hanging wall. Diagonally down always points to footwall.
the movement on the UPPER PART ONLY of the hillside shown in the drawing below is a
rotational slide that is more common in soil and unconsolidated material than in rock
sedimentary processes are responsible for producing deposits of
salt, gypsum, limestone, and banded iron formation
which soil drains the most quickly
sandy soil becuase it has the largest pore spaces and they are interconnected
Cause of Tsunami
"1)generated on ocean floor 2)movement along dip slip fault 3) large earthquake displacing a large volume of water ->subduction zones"
Reservoirs of Water
"1)oceans 2)glaciers 3)groundwater"
Earthquakes in the Pacific Northwest
"1700 Earthquake, Crustal Earthquakes - The Seattle Fault, Benioff Earthquakes. 1) Subduction zone earthquakes- shallow-tsunami producing 2)benioff earthquakes(juan de fuca)- deep earthquakes along subducting plate- more frequent 3) crustal plates- shallow- can be large- over
Crustal Earthquakes (Seattle Fault)
"Crustal Reverse fault. Lots of fault zones-has potential for damage"
Benioff Earthquakes
"Deep earthquakes from normal earthquakes Reaccurance 20-30 yrs. Depth- 50 km"
Hydrologic Cycle
"Evaporation
Material Amplification
"Low amplification -------------- >high --- >Hard igneous, sed. Rocks, alluvium, silt/mud--- >"
Tsunami - DART
"Measures water pressure-Bottom pressure reader and tsunami goes over buoys. Pressure reader changes reading while wave passes overà measures change in water pressure which gives you the wave height"
Which of the following statments about slope stability and downslope movements is CORRECT?
when rivers are dammed, the increased water pressure in the resivoir behind the dam may weaken rocks with open fractures
Wave Length of Tsunami
*Deep Ocean* Long Wave Length, small aptitude, high velocity. Wave length = difference between crest. *Shallow WaterU Velocity slows, all of the water in long wavelength piles up to form high waves.
1700 Earthquake
...
Know the scale and difference in size between different increments of the scales
...
Domes and Basins
..., formed as a result of vertical crustal motion. Domes look like an overturned bowl and result from crustal upwarping. Basins look like a bowl and result from subsidence
Earthquake Requirements
1. Generated on the ocean floor 2. movement along a dip slip fault 3. a large earthquake displacing a larger volume water (magnitude 7 minimum). Shallow earthquakes -> Subduction zone
Where to measure average velocity
2/3 way down in the middle of the stream
What are the two kinds of folding?
Anticlines, syncilines.
Floods
Describe a flood by it's discharge.
What is tensional stress? What does it produce?
Coming apart, normal faults.
What is compressional stress? What does it give us?
Coming together. It gives us: folds, resverse and thrust faults.
What are the three stresses
Compression, tensional, shear.
Landslides
Hawaii., a slide of a large mass of dirt and rock down a mountain or cliff
Locating the epicenter of an earthquake
If we draw a circle with a radius of 2k KM then we know the earthquake is somewhere along the circle. If you make 3 circles and the place where the circles intersect, that's the epicenter.
Measuring the size of earthquakes
Magnitude scale, richter scale.
Strike and Dip
Measuring the orientation of planar surfaces
Body Waves
P and S waves
Reverse Faults
Reverse faults have dips greater than 45o
Normal faults
Tensional stress. Hanging wall block moves down relative to the footwall block. Accommodate lengthening or extension of the crust.
What is the dip?
The angle that is tilting
Stream flow and velocity
We can measure stream flow through velocity. Throw a marshmellow in a river and see how far it moves in a certain amount of time. Water will move quick if the slope is steep. Velocity is driven by the slope (gradient). The amount of drop over time.
Speed of Tsunami
When a tsunami is cruising through the pacific ocean, they travel as fast as an airplane flies. If we have an earthquake from cascade, it would take 15 mins to the coast of Washington. Slows down in Shallow water.
Liquefaction
When we take cohesive sediment, usually finer grain, shake it and it turns into a liquid. It flows like a fluid.
Distribution of Velocity in a channel
You find the max velocity at surface in the middle. Slowest along the sides.
the figure below shows a cross sectional view of soil arching over a solution fracture in limestone. what has the potential to develop here?
a sinkhole
which of the following statements related to water resources is correct?
consumptive water uses describes irrigation water and water that is consumed by people and livestock that doesn't immediately return to the water resiviour from which it was taken
nonpoint source pollution
currently includes agricultural and residential runoff and acid mine drainage
pharmaceuticals and personal care products that go down the toilet, drain, or through the washing machine
end up in both surface water and groundwater
once heavy metals such as mercury are in surface waters, they
enter the food chain and become concentrated through biomagnification
what fuels tropical cyclones
evaporation of warm seawater
Thrust Faults
have dips less than 45o
beach nourishment
involves dredging sand from offshore and pumping it to a beach
what is happening to the ogallala aquifer
it is an example of groundwater mining, where in many places the amount of water pumped out greatly exceeds the natural recharge
which soil holds some water and allows some water to drain and why
loam becuase the pore spaces between larger particles help drain water, and the pore spaces between smaller particles help hold water
compacted soils
lose their ability to absorb water, so runoff increases
which mining method would most likely be used to mine a low grade disseminated gold deposit located close to the surface
open pit mining
why do fish die when large amounts of manure are spilled into a river
oxygen in the water is consumed by the bacteria that break down the concentrated organic matter in the manure
Tsunami
seismic sea wave that begins over an earthquake focus and can be highly destructive when it crashes on shore
what kind of mass movement is in the drawing below? (original position -(down slope) moving block?
slide
what methods can be used to try and REDUCE the risk of mass wasting?
small retaining walls to provide support at the base of overstepped slopes
which of the following statements about soil is correct?
soil characteristics are a function of parent material, organisms. topography, climate, and time
which of the following statements about soil is CORRECT?
soils are weathering products that provide a record of past enviroments and climate
which of the following statemnts about mineral resources is correct
the enrichment fator is the number of times the average crustal concentration of a metal must be increased before the ore can be mined at a profit
Precipitation
the falling to earth of any form of water (rain or snow or hail or sleet or mist)
approx 75 different chemical elements are used to make a smart phone. the more elements that are used in the consumer products
the harder they are to recycle
Epicenter
the location at the surface directly above the focus
Focus
the source of the earthquake at depth
how did the construction of levees along the Mississippi river in southern Louisiana contribute
they prevent flooding, no new sediment is getting deposited on either side of the river to help build up the land
what kind of aquifer do the following statements describe? the water level in a well is at the water table the aquifer is recharged directly from the infiltration of surface water and precipitation
unconfined aquifer
wastewater treatment plants
use a primary treatments process where grease and oils float to the top and solids settle to the bottom as sludge
which of the following statements about storm surge is CORRECT?
water is pushed farther inland when the shore is gently sloping
Run off
water that flows over the ground surface rather than soaking into the ground
what is meant by virtual water
water that is embedded in traded agricultural and industrial commodities