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Earthquakes

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					Earthquakes


  1. Earthquake: the shaking and trembling that result from the movement
     of rock beneath Earth’s surface.

  2. Seismic waves carry the energy of the earthquake away from the focus,
     through Earth’s interior and across the surface. There are 3 categories of
     seismic waves; p-waves, s-waves, and surface waves.

     The 1st to arrive are the primary waves, or p-waves. P-waves are
     earthquake waves that compress and expand the ground like an
     accordion. S-waves or secondary waves are earthquake waves that vibrate
     from side to side as well as up and down. Surface waves move more
     slowly than p-waves and s-waves, but they can produce severe ground
     movements. Some surface waves make the ground roll like ocean waves.
  3. Focus; the point beneath the Earth’s surface where rock that is under
     stress breaks, triggering an earthquake

     Epicenter: the point directly above the focus on the surface
     Fault: is a break in the crust where slabs of crust slip past each other.
  4. Hazards of earthquakes; shaking of the earth, power lines fall, gas line
     burst, fires, and building falling.

  5. To determine where an earthquake occurred you need to find the
     difference in the arrival of p-waves and s-waves from 3 different stations.
     Use the chart to determine the distance around the station center. Draw a
     circle around the station center. Where the 3 circles meet is where the
     earthquake occurred.
Volcanoes

  1. Shield Volcano; thin layers of lava pours out of a vent and hardens on
     top of a previous layer. The lava flows gradually build a wide, gently
     sloping mountain. Form from a hot spot. Quiet eruptions.
     Cinder Cone: when cinders erupt explosively from a volcanic vent, they
     pile up around the vent, forming a cone shaped hill.
     Composite: lava flow alternates with layers of ash, cinders, and
     bombs, which has both quiet and explosive eruptions. Tall cone
     shaped mountain.
  2. Shield- quiet
     Cinder cone-explosive
     Composite- quiet and explosive
  3. Most volcanoes occur along diverging plate boundaries, such as mid-
     ocean ridge or in subduction zones around the edge of oceans. Some
     volcanoes can form at hot spots.
  4. High in silica: very thick, light colored, lower in temperature, cause
     explosive eruption
     Low in silica: thin, dark colored, hotter in temperature, cause quiet
     eruptions
  5. Hot spring form when a body of water is heated up from magma. It
     makes it way to the surface through a crack in the rock.
  6. Hazards of volcanoes lava, pyroclastic flow, fire, gases
Weathering and Erosion


  1. Mechanical/Physical weathering: the breakdown of rock into smaller
     pieces of the same material without any change in its composition

     Chemical weathering: the breakdown or decomposition of rock that takes
     place when minerals change through chemical processes. The agents of
     chemical weathering are water, oxygen, carbon dioxide, and acid rain.
  2. The most important factors that determine the rate at which weathering
     occurs are the type of rock and climate.

        a. Climate- wet climates allow weathering to occur faster. Chemical in
           hotter temperatures and mechanical/physical in colder
           temperatures.

        b. Rock type the softer the rock such as Sedimentary the easier the
           breakdown the harder the rock such as metamorphic the hard it is
           to breakdown.

  3. Release of pressure- as erosion removes material from the surface of a
     mass of rock; pressure on the rock below is reduced. This release of
     pressure causes the outside of the rock to crack and flake off like the
     layer of on onion.

     Ice wedging- when water freezes in cracks of rock, it expands and makes
     the crack bigger.
     Plant growth- root of trees and other plants enter cracks in rocks. As the
     root grows, the force the crack apart.
     Carbon dioxide- can mix with water and produce a weak acid which and
     destroy rocks.
     Water- will erode rock.
     Abrasion- sand and other rock particles that carried by wind, water, or ice
     can wear away exposed rock surfaces like sandpaper on wood.
     Animal action- animals that burrow in the ground loosen and break apart
     rocks in the soil.
  4. Weathering: The process by which natural forces break down rocks.

     Erosion: The process in which sediment is picked up and moved from one
     place to another.
     Deposition: the process in which transported sediment is laid down.
  5. Soil is a mixture of four material; weathered rock particles, organic
     matter, water, and air. Soil that forms in an area will depend on a
     number of factors which include: the kind of rock, the area’s climate, or
     overall weather pattern over time, the landforms in the area, such as
   mountains and valleys, the plant coverage, the animals and other
   organisms in the area, and time.

6. All mass movement/mass wasting is due to gravity.

      a. Slump- a mass of rock and soil that suddenly slips down a slope in
         one large mass.

      b. Creep- the very slow downhill movement of rock and soil. Can’t
         see happened, it occurs over a period of time.

      c. Rockslide/rock fall- individual blocks of rock drop suddenly and fall
         freely down a cliff or steep mountain. Large mass of rock slides
         down the hill or mountain as a unit.

      d. Mudflow/mudslide- a mixture of rock, soil, and plant.

7. Moving water is the major agent of erosion that shaped Earth’s land
   surface. A river creates valleys, waterfalls, floodplains, deltas, alluvial
   fans, meanders, and oxbow lakes.

8. The 2 processes by which glaciers erode the land are plucking and
   abrasion. Plucking picks up rocks by freezing to the bottom of the
   glacier. Abrasion is when small rock fragments are carries in the glacier
   and wear away rock.

9. Wave erosion is caused by ocean water shaping and wearing away the
   shore line.

      a. Longshore drifts is the zigzag movement of sand along the beach.

      b. Longshore currents is the movement of water along a shore as
         waves strike the shore at an angle.

      c. Barrier island narrow island that develops parallel to a coast, due to
         the deposition of sand.

   Waves can also cut caves into the land and create sea pillars.
10.      Wind erosion shapes the land by the wind blowing particle of sand.
   This can create dunes, which is a mound of sand built up by wind. It can
   also cause abrasion which wears away rock.
Weather



 1. Atmosphere- the layer of gases that surrounds the planet.
        a. Oxygen=21%
        b. Nitrogen =78%
        c. Other gases such as water vapor, carbon dioxide, helium,
            methane=1%
     Earth’s atmosphere is made up of nitrogen, oxygen, carbon dioxide,
     water vapor, and many other gases, as well as particles of liquids and
     solids
 2. Air has pressure because it has mass. Dense, cool, air exerts more
    pressure than less dense warm air. The result of weight of a column of air
    pushing down on an area. More pressure at the bottom of a mountain
    than on the top.
 3. A barometer is used to measure air pressure.
 4. There are 4 main layers of the atmosphere that are classified according to
    changes in temperature.
        a. Troposphere- where weather occurs, layer that we live in.
        b. Stratosphere- where you would find the ozone
        c. Mesosphere- where meteoroids burn up
        d. Thermosphere
 5. The ozone layer absorbs ultraviolet radiation. 3 atoms of oxygen. It
    absorbs energy from the sun; the energy is converted into heat, warming
    the air.
 6. Heat is transferred by radiation conduction, and convection.
        a. Radiation- direct transfer of energy by electromagnetic waves
        b. Conduction- direct transfer of heat from one substance to another
            substance that it is touching.
        c. Convection- transfer of heat by the movement of a fluid (gas or
            liquid)
 7. Winds are caused by a difference in air pressure. The difference in air
    pressure is caused by unequal heating of earth’s surface.
8. Cold air masses tend to be more dense than a warm air mass, due to the
   molecules being closer together. Since the cold air mass is more dense it
   tends to sink and go under a warm air mass.
9. Local winds are caused by unequal hating of Earth’s surface within a small
   area.
   Sea Breezes- a wind that blows from a lake or ocean onto land, this occurs
   in daytime due to earth’s surface heating up more quickly.
   Land Breezes- the flow of air from land to a body of water. This occurs at
   night because the land tends to release it heat more quickly than the
   water.
   Global winds- winds that blow steadily from specific directions over long
   distance. This is created by unequal heating of Earth’s surface. They are
   trade winds, prevailing westerlies, and polar easterlies.
10. Coriolis Effect- the way the earth’s rotation makes the wind curve. In the
   Northern hemisphere the winds gradually turn toward the right and in the
   southern hemisphere the gradually curve to the left.
11. Cumulus- looks like rounded piles of cotton. Means heap or mass, usually
   indicate fair weather, they may grow in height.
   Stratus- forms in flat layers usually covers the entire sky, may produce
   drizzle, rain, or snow, they are low level clouds.
   Cirrus- wispy, feathery clouds, form at high levels where temperatures are
   very low. Mostly made up of ice crystals.
12. Maritime Tropical- warm, humid air masses form over oceans near the
   tropics. In the summer it brings hot, humid weather. In the winter it can
   bring heavy rain or snow.
   Maritime Polar- cool, humid air masses that form over the icy cold North
   Pacific and North Atlantic oceans.
   Continental Tropical- hot, dry air masses that form only in the summer
   over dry masses of the southwest and northern Mexico.
   Continental Polar- large polar air masses form over central and northern
   Canada and Alaska. They bring cool and cold air. The air masses can
   form near the Arctic Circle and can bring bitterly cold weather with very
   low humidity.
13. Thunderstorms form within large cumulonimbus clouds. They form on
   hot humid afternoons in spring and summer.
14. Parts of a hurricane eye, which is the calm winds and the eye wall which is
   where the high winds and storms come from.
15. Tornado Watch” - tornadoes possible in your area.
   “Tornado Warning” - tornado has been seen in the sky or on a weather
   radar.
   The safest place during a tornado is a basement of a well-built building.
   Move to the middle of the ground floor.
   Stay away from windows and doors.
   Lie flat on the ground under sturdy furniture.
   Move to a building or lie flat in a ditch
16. A meteorologist is someone who studies weather.
17. The reason why we have season is due to the fact that the earth is tilted.
   During the summer the earth’s northern hemisphere is tilted toward the
   sun.
18. Climate refers to the average year after year conditions of temperature,
   precipitation, winds, and clouds in an area.
19. Two main factors of determining the climate of a region is temperature
   and precipitation.

				
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posted:11/24/2011
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