Exam 3
Rock Elasticity
-Higher elasticity results in higher velocities
Rock Density
-higher density results in higher velocities
What would be the angle of inclination of rocks in Ecuador (equator)
0º
Nuclear Fission
1) Neutrons bombard the Uranium atom 2) Uranium atom splits and emits neutrons and heat energy 3) Chain Reaction
Frequency of flooding is measured by:
1) Recurrence interval 2) Exceedence probability
Continent-continent collisions result in:
1. Closing of an ocean basin 2. Increasing the surface area of a continent 3. Thickening the crust -->high topography 4. If crust becomes TOO thick it collapses
What temperature do organic rich sediment need to achieve to transform into oil?
100-120º
The angle of inclination is ___________ at the magnetic north pole.
90º
Seismograph
A device that records ground movements caused by seismic waves as they move through Earth
continental shelf
A gently sloping, shallow area of the ocean floor that extends outward from the edge of a continent
Meander cutoff
A new, shorter channel across the narrow neck of a meander.
P Wave
A type of seismic wave that compresses and expands the ground.
S Wave
A type of seismic wave that moves the ground up and down or side to side
Discharge
An outflow of water from a stream, pipe, groundwater aquifer, or watershed. The rate of flow = volume / unit time (e.g. cubic feet/second, ft3/s)
Hydraulic Radius calculated by
Area / Perimeter
Mature Stage
Atlantic Ocean
Earthquake Belts
Bands around the edges of the continental plates and in areas where two plates come together. The belt is that connection of the plates. The Pacific Ring of Fire is all the edges of these plates.
Change in magnetic inclination
Changes with latitude
Where do we have the highest velocity of Seismic Waves?
Core
How do we calculate Discharge?
Discharge (Q) is measured using a simplified form of the Continuity Equation: Q = V x A V = average flow velocity A = cross sectional area of water (channel)
Embryonic Stage
E African Rift Valley
Tsunami
Earthquake produced Tidal Wave • Long wavelength to short wavelength • Low Amplitude to high amplitude
Richter scale
Earthquakes are classified according to their magnitude, a measure of the amount of energy released during the EQ.
Mercalli Intensity Scale
Earthquakes classified by their intensity which is based on the observed damage to various structures
Where do Earthquakes Occur?
Earthquakes occur along faults where the temperature of the crust is "low" ~300o and below
Where do earthquakes occur?
Earthquakes occur along faults where the temperature of the crust is "low" ~300o and below
Velocity of Seismic Waves varies with rock properties
Elasticity & Density
Faults Move (Slip) Two Different Ways
Fault creep and stick-slip
Stick-Slip
Fault stays "locked" storing up elastic energy, then suddenly slips, releasing the stored energy. Big EQs
Oil Traps
Geologic environments that allow economically significant amounts of oil and natural gas to accumulate underground All oil traps consist of a reservoir rock and a cap rock.
Resovoir rock
HIGH porosity & permeability
Crest (wave)
Highest point of a wave
Suture Stage
Himalayan Mountains
Wavelength
Horizontal distance between the crests or between the troughs of two adjacent waves
Cap Rock
LOW porosity & permeability
Greenhouse effect is caused by?
Long wavelength
Trough (wave)
Lowest point of a wave
polar wandering curves
Magnetic record trail that can be used to determine movement of a plate over time
Remnant Stage
Mediterranean Ocean
Greenhouse effect
Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases
Immature Stage
Red Sea
Earth's layered structure
Seismic waves tell us about the shape and composition of the interior of the Earth:
Compression results in:
Shortening and thickening of the crust
Fault Creep
Slow, gradual displacement (motion) Small EQs
What is forming the S wave Shadow Zone?
Something opaque to shear waves - i.e. something liquid
Alluvial streams
Streams that cut within reworked stream-deposited material
Drainage Basin
The area from which a single stream or river and its tributaries drains all of the water
Seismic Refraction
The bending of seismic waves as they pass from one material to another.
Falling Limb (Hydrograph)
The decrease in river discharge as the river returns to its normal level
Paleomagnetism
The study of natural remnant magnetization preserved in rocks in order to determine the intensity and direction of the Earth's magnetic field in the geologic past
S-Wave Shadow Zone
Those areas more than 103 degrees from an earthquake focus where no S-waves are recorded.
Lag Time (Hydrograph)
Time between peak rainfall and peak discharge
Manning's Equation
V = (1.5 R ^(2/3) x S^(1/2) / n V = Average Water Velocity n = Mannings Roughness Coefficient ( a measure of the resistance to flow) R = Hydraulic Radius ( a measure of the efficiency of the channel cross section) S = Slope of the Energy Gradient (approximated by the slope of the channel)
What two values do we use to measure Discharge
Velocity and Area
Earthquake
Vibration of the Earth caused by the rapid release of energy. Often, earthquakes are caused by slip on faults.
Geomagnetic reversal
When the north magnetic pole becomes the south magnetic pole and vice versa
Fe-rich minerals become magnetized ____?
When they cool below their curie point and become magnetized in the direction parallel to the existing magnetic lines of force.
Oxbox lake
a cresent-shaped body of water formed when sediments deposited by a river cut off a meander from the river.
Hydrograph
a graph which shows the the discharge of a river, related to rainfall, over a period of time
Triangulation Earthquakes
a method that utilizes the arrival time difference of S&P waves at three seismograph stations to locate the focus point of an earthquake
Epiccenter
a point on Earth's surface right above the focus of an earthquake
Fault scarp
a small step on the ground surface where one side of a fault has moved vertically with respect to the other
continental slope
a steep incline of the ocean floor leading down from the edge of the continental shelf
Meandering Stream
a stream with a channel that curves or loops back and forth on a wide floodplain
recurrance interval
average number of years (n) between events of similar or greater magnitude (m) RI = N + (1 / m)
Point bar
deposit of sediment build up by a river on the inside bend of a meander
Cutbank
eroded stream bank on the outside of a meander curve
meander scrolls
indicate historical migration of meander bends
The Earth's magnetic field has reversed polarity throughout geologic time. Evidence for this phenomenon is
magnetic seafloor stripes
Magnetic Stripes
provide evidence of sea floor spreading when they show the reversal of magnetic fields
Nuclear Energy
radioactive materials (Uranium) release energy by the process of Nuclear Fission.
Gravitational collapse results in
stretching and thinning of the crust
angle of inclination
the angle that the line of force makes on the horizon the angle between the Earth's magnetic field and its surface.
continential rise
the gently sloping section of the continental margin located between the continental slope and the abyssal plain
Amplitude (wave)
the height of a wave's crest
Hydrologic cycle
the movement of water through the biosphere
Seismogram
the record of an earthquake's seismic waves produced by a seismograph
Elastic Rebound
the sudden return of elastically deformed rock to its undeformed shape
Curie point
the temperature at which a mineral become magnetized (~580 C).
Period (wave)
the time that elapses between passing crests (or troughs)
Rainfall
the total rain, snow, or sleet that falls in a period of time
hypocenter
the underground focus point of an earthquake.
abyssal plain
very level area of the deep-ocean floor, usually lying at the foot of the continental rise
Runoff
water that flows over the ground surface rather than soaking into the ground = Rainfall - Infiltration
Components of a wave
wave length, trough, crest, amplitude
Seismic Survey
when a shock wave is sent into the ground surface, and the reflected sound waves are recorded
What Determines the Volume of Floodwaters at a Specific Location?
• Amount of Rainfall (inches or cm.) • Amount of Infiltration (inches or cm.) • Area of the Drainage Basin (mi2 or km2)
The Wilson Cycle
• Embryonic Stage • Immature Stage • Mature Stage • Declining Stage • Remnant Stage • Suture Stage
Streams can move by one of the following processes:
• Lateral Migration • Meander Cutoff
Isostasy
• Less dense crust floats on top of the denser and deformable rocks of the mantle • Concept of floating crust in gravitational balance is called isostasy • If weight is added or removed from the crust, isostatic adjustment will take place as the crust subsides or rebounds
Lateral migration
The sideways shift in the position of a stream channel over time
Sinuosity
The sinuosity of a stream is a measure of how much it is meandering.
Waves Speed
P: Fast S: Intermediate Surface: Slow
Waves Period
P: Shortest S: Intermediate Surface: Longest
Waves Amplitude
P: Smallest S: Intermediate Surface: Largest
Waves Medium
P: Solid, liquid, gas S & Surface: only solids
Declining Stage
Pacific Ocean
Flood peak
The highest level that a river reaches during a flood.
Rising Limb (Hydrograph)
The increase in river discharge as rainwater flows into the river
Exceedence Probability
The probability (p) of an event of a particular magnitude being equaled or exceeded any given year is. P = 1 / RI