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68 Cards in this Set
- Front
- Back
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How old is the earth?
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4.6 billion years
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What are the 3 ways material can be described when under stress and how do they react?
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Elastic (recovers)
Ductile (deforms) Brittle (breaks) |
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Describe the tectonic cycle
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Seafloor spreading occurs at spreading centers as magma rises, solidifies, and adds onto plate edges; the plates move to subduction zones and the denser plate is pushed down under into the mantle where it remelts.
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Name the 3 types of plate boundaries
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Convergent (subduction zone- BIG quakes), Divergent (spreading centre- little quakes), and Transform (sliding motion- Medium quakes)
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What is a hotspot? What happens at a hotspot?
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Lava rises in a plume through the crust and form volcanic islands. As the plates move, volcanos move off of the hotspot, forming new islands.
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What is evidence of seafloor spreading?
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Reversal of poles, age of crust as it moves farther away, young age of crust.
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Define the dip and strike of a fault.
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The dip is the slant of the fault in 3D, the strike is the lateral horizontal line of the fault 2D on the surface.
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What is a normal fault? Where do they often occur? What kind of "zone" shows they happen?
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When the hanging wall (the slanting "overhead" rock) moves DOWN relative to the footwall. Often at divergent zones.
The Zone of Omission where continious rock layers are ommited because one moved down |
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What is a reverse fault? Where do they often occur?
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When the hanging wall (the slanting "overhead" rock) moves UP relative to the footwall. Happens at convergent zones.
The Zone of Repetition where continious rock layers repeat in an area because one has moved up above the other. |
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What is a strike-slip fault? Where do they often occur?
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Rocks move alonside past each other. When standing over a strike-slip fault, the side moving towards you defines it (ie if the right is moving, it is a right-lateral fault).
They happen at Transform Faults |
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Define hypocenter and epicenter
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Hypocenter: where in the earth below ground earthquake originates
Epicentre: directly above hypocentre on the corresponding earth surface. |
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What does it mean when a fault is right-stepping or left-stepping?
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Strike-slip faults must overcome bends, so the fault must "step" to a side to get around.
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Describe the parts of a wave
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Amplitude: height from lowest valley to highest crest.
Wavelength: distance between 2 crests or 2 troughs. Period: time it takes for 1 wavelength to pass |
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How do P waves work? What does P Wave stand for?
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P waves are Primary Waves that arrive first. They move in a push-pull motion like a slinky. They can travel through all materials. High frequency, short period
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How do S waves work? What does S wave stand for?
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S wave is Secondary Wave. They come after P waves in a typical wave motion. They shear or shake particles. They can only move through solids. They move up and down, side to side. CAUSE THE DAMAGE.
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What are body waves?
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Earthquake waves that are high freq., short period, that move through the whole planet body
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What are surface waves? How do they behave?
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Surface waves travel near earth surface, catagorized as Love and Rayleigh waves. Low freq., LONG periods.
Rayleigh move in backwards ellipses. Feel like ocean waves. Arrive last. |
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If an earthquake increases from a 4 to 5, how much larger is the amplitude?
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10 fold, so the energy in a richer 5 is 10 times greater than a 4.
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What kind of building would be most hurt by S and P waves?
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Rigid constructed ones or short buildings, as their frequencies are amplified
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/What kind of building would be most hurt by surface waves?
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Tall buildings with low frequency vibration.
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What causes a tsunami??
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A large impact in the water like volcano debris/meteorites/landslides, or more common, an underwater movement (earthquake)
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What makes a tsunami different from a regular ocean wave?
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Tsunamis have very long periods and huge velocity. Their huge wavelengths come from constantly dragging on the ocean floor. Waves arrive in between a 10-60 min interval
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How do subduction zones make volcanos? What kind do they make?
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Subduction pushes water-saturated ocean crust into the magma and the water lowers the melting point of rock. Rising magma melts the continental crust above and rise into volcano. They make tall, andesitic-rhyolitic volcanos
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What kind of volcanic activity happens at spreading centres?
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Basaltic, happens in ocean floor.
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What are the most common elements in magma?? What happens when magma cools?
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Oxygen and silicon. When magma cools, some O2 and silicon joins together and the crust contains mostly these oxides.
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What is the difference between plutonic and volcanic rock?
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Plutonic is formed below the surface while volcanic is made once it reaches the surface.
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What is the relationship between viscosity and temperature and Si02 content?
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As temp rises, viscosity and Si02 content decreases .
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Describe basaltic lava (vis, temp, types of volcanoes)
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High temp, low viscosity, comes mostly at spreading centres, Icelandic and Hawaiian type volcanos, peaceful
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Describe andesitic lava (vis, temp, types of volcanoes)
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Med. temp, med. vis., comes from Strombolian and sometimes Plinian volcanos, medium volitility
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Describe rhyolitic lava (vis, temp, types of volcanoes)
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Low temp, high viscosity, comes from Vulcanian and Plinian volcanos, VERY explosive.
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Describe some volcanic explosion effects?
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Lahars- hot mudflows
Pyroclastic flows- cloud of hot ash and gasses Pyroclastic bombs- partially solid magma that shoots out of the volcano Ash- fine particles of dust that can coat areas for miles Earthquakes- usually under 6 richter but still severe. |
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Where does the energy for natural disasters come from? (3 types)
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Latent storage of energy within earth (from terrestrial impact and decay of radioactive isotopes), gravitational energy, and solar energy.
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Which type of crust is denser and thicker?
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Oceanic!
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What happens when two oceanic plates collide?
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The older, denser, colder plate subducts
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Describe a blind thrust fault
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Less of an angle than regular reverse fault. One piece is thrust up over the other hiding the fault under the surface.
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Decribe a scoria cone
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Low, conical hill type, commonly produced in a single eruption, aka Cinder cone. Med. velocity/viscosiy and low volume.
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Describe a stratavolcano
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aka composite volcano,
steep sided and symetrical, built from layers of pyroclastic debris and bapped with high vis. lava. |
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Describe a shield volcano
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Formed by lava flows, low and very wide, low vis and high volume.
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Describe the types of Mass Movements!
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Fall- elevated rock mass separates along joints or other weakness, free fall or rolls.
Slide- movement along a sloped or curved plane either in regular transitional slide, or the sloping Rotational Slide as it moves down and out on axis. Subsidence- a collapse as ground moves down sometimes in a gentle sag or fast sinkhole. |
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How does the Angle of Repose work?
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When material is dumped out, it forms angle of repose, usually does not exceed 30-37 degrees, and when it does, it is overcome and causes slope failure to readjust back to the angle of repose.
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Descibe sediment flows
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Contains water!
Includes mud flows, avalanches, slurry flows, etc. |
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Describe the latent heat release and absorbtion in the water cycle.
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Liquid to solid (freezing)- heat is released
Liquid to gas (evaporation)- heat is absorbed Gas to liquid (condensation)- heat is released Solid to liquid (melting)- heat is absorbed Gas to solid (deposition)- heat is released Solid to gas (sublimation)- heat is absorbed. |
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Describe a warm front.
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Colder air meets a warm airmass and the warm air pushes up and over the cold air. Fair weather!
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Describe a cold front.
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Colder air meets warm air, and the cold air forces towards the warm, pushing the warm air straight up. Bad weather!
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What are the greenhouse gasses?
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CO2, CFCs, Methane, Nitrous Oxide, ozone.
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What is El Nino??
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Ever 2-7 yrs, the typical Pacific current flow changes, trade winds weaken and thus the whole ocean has warmer water across it's top, when normally towards the Americans, the trade winds keep warm water flowing towards Australia and cooler over by Peru. El Nino brings warm moist air to the Americas, which brings rain.
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Where does the energy for natural disasters come from? (3 types)
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Latent storage of energy within earth (from terrestrial impact and decay of radioactive isotopes), gravitational energy, and solar energy.
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Which type of crust is denser and thicker?
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Oceanic!
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What happens when two oceanic plates collide?
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The older, denser, colder plate subducts
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Describe a blind thrust fault
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Less of an angle than regular reverse fault. One piece is thrust up over the other hiding the fault under the surface.
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Decribe a scoria cone
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Low, conical hill type, commonly produced in a single eruption, aka Cinder cone. Med. velocity/viscosiy and low volume.
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Describe a stratavolcano
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aka composite volcano,
steep sided and symetrical, built from layers of pyroclastic debris and bapped with high vis. lava. |
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Describe a shield volcano
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Formed by lava flows, low and very wide, low vis and high volume.
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Describe the types of Mass Movements!
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Fall- elevated rock mass separates along joints or other weakness, free fall or rolls.
Slide- movement along a sloped or curved plane either in regular transitional slide, or the sloping Rotational Slide as it moves down and out on axis. Subsidence- a collapse as ground moves down sometimes in a gentle sag or fast sinkhole. |
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How does the Angle of Repose work?
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When material is dumped out, it forms angle of repose, usually does not exceed 30-37 degrees, and when it does, it is overcome and causes slope failure to readjust back to the angle of repose.
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Descibe sediment flows
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Contains water!
Includes mud flows, avalanches, slurry flows, etc. |
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Describe the latent heat release and absorbtion in the water cycle.
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Liquid to solid (freezing)- heat is released
Liquid to gas (evaporation)- heat is absorbed Gas to liquid (condensation)- heat is released Solid to liquid (melting)- heat is absorbed Gas to solid (deposition)- heat is released Solid to gas (sublimation)- heat is absorbed. |
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Describe a warm front.
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Colder air meets a warm airmass and the warm air pushes up and over the cold air. Fair weather!
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Describe a cold front.
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Colder air meets warm air, and the cold air forces towards the warm, pushing the warm air straight up. Bad weather!
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What are the greenhouse gasses?
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CO2, CFCs, Methane, Nitrous Oxide, ozone.
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What is El Nino??
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Ever 2-7 yrs, the typical Pacific current flow changes, trade winds weaken and thus the whole ocean has warmer water across it's top, when normally towards the Americans, the trade winds keep warm water flowing towards Australia and cooler over by Peru. El Nino brings warm moist air to the Americas, which brings rain.
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What is La Nina?
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Colder water comes to the Americas with the very strong trade winds. Low rain in southern America, results in more hurricanes.
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What is the Coreolis Effect?
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Things in space move to the right due to earth's rotation. No effect @ equator but things move to right in N. Hemi.
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What happens at a low pressure zone?
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Warm moist air rises up, a counter-clockwise rotatation occurs, is what hurricanes/tornados do.
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What happens at a high pressure system?
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Cool dry air sinks, clockwise rotation occurs, called "anticyclonic"
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Describe the movements of the winds around the world.
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Warm air rises at equator, sinks into subtropics, air at poles sinks and flows to equator. Middle zones are transfer areas where warm air rises and moves to poles, and the cold air moves to the equator.
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Describe how air moves during the summer and then during the winter.
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Summer: Warm air rises, creates high pressure air masses that push out over ocean and descend. Rain over land.
Winter: Warmer ocean air supplies heat to cool air flowing off land. Warm air rises, producing high air pressure masses above. Rain over ocean. |
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Define tilt, wobble, and eccentricity
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Tilt- the change in the inclination of the earth's axis.
Wobble- the change in the precision of the equinoxes and the direction of the spin axis. Eccentricity- the change in shape of orbit. |
