The Dynamic Earth

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The Dynamic Earth
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Banda Aceh Shore (Before Tsunami)
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Banda Aceh Shore
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Banda Aceh Northern Shore (Before Tsunami)
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Banda Aceh Northern Shore
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Banda Aceh Before Flooding
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Banda Aceh Flooding
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Banda Aceh City Overview (Before Tsunami)
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Banda Aceh City Overview
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BBC Tsunami Tsunami pdf
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Earths Internal Zones

• CORE
• 1/2 radius
• 2 parts
• 16 volume, but 31 of mass
• inner core - solid, mostly iron, 3400C
  3,000,000Gs gravity
• outer core - liquid, 3700-4300C

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Earths Internal Zones

• MANTLE
• solid
• 10-2900km from surface
• 82 of volume, but 68 of mass
• iron, plus O, Si, Mg
• low velocity zone
• upper part of mantle
• semi-liquid (1-10)
• seismic waves slow down
• asthenosphere

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Earths Internal Zones

• CRUST
• thinnest section
• 2 volume, 1 mass
• 10-65 thick
• earthquakes are generated
• plate movement
• lithosphere

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determining the earths interior

• seismic wave A wave that travels outward from the
  site of an earthquake through the Earth.
• First to arrive at a monitoring site after a
  distant earthquake are the primary waves, or
  P-waves. These are pressure waves, a little like
  ordinary sound waves in air

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• Seismic P-waves usually travel at speeds ranging
  from 5 to 6 km/s and can travel through both
  liquids and solids.
• Some time later (the actual delay depends on the
  distance from the earthquake site), secondary
  waves, or S-waves, arrive. These are shear waves.
  
• S-waves cause side-to-side motion, more like
  waves in a guitar string.
• S-waves normally travel through Earth's interior
  at 3 to 4 km/s they cannot travel through
  liquid, which absorbs them.

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Seismic Waves
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Composition of Earths Crust
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Types of Crust Oceanic

• 71 of surface, dense, 10km thick
• oceanic ridge system
• 80,000 km long
• 1500-2500km wide
• 2-3km wide
• Abyssal Floor
• deep ocean basins, 5km below sea level
• trenches
• 8 km below sea level

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Abyssal Sea Floor and Trenches
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Continental Crust
Oceanic Ridge System and Continental Shelf

• Higher and thicker than oceanic crust
• averages 35km thick
• lower density--gt floats
• continental shelf- underwater portion of the
  continental crust

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Crust Plates

• 100km thick (crust and mantle) - lithosphere
• move over the semi-liquid asthenosphere
• move at the same rate as finger nails grow (1
  inch/year)

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Plate Tectonics

• Theory that explains the apparent movement of
  Earths plates and the geological process that
  occur at the boundaries
• The movement of the plates
• is an explain the biogeography of organisms
• is responsible for the earth surface features
• concentration of minerals

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Plate Tectonics

• Evidence
• polar wander curves
• distribution of organisms
• distribution of ice
• shape of continents
• continued activity at boundaries

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Plate Boundaries
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PAST CONTINENTAL DRIFT
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Divergent Boundaries

• Plates move in opposite directions
• ocean spreading
• creates ridge
• youngest area of ocean
• earthquakes and volcanoes

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Convergent Boundaries

• Plates move toward each other
• often oceanic plate is subducted under
  continental plate
• subduction zone makes a trench
• earthquakes and volcanoes
• oldest part of ocean

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Transform Fault

• Plates move in opposite, parallel directions
• San Andreas
• only earthquakes

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External Processes Break Down Earths Surface

• Erosion
• material is broken down, worn away, and moved
• streams are primary source
• also wind and gravity

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External Processes Break Down Earths Surface

• Weathering
• mechanical - a large rock is broken down into
  smaller rocks (frost wedging)
• chemical - a rock is decomposed by chemical
  reactions (oxidation, acid rain, hydration)

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External Processes Break Down Earths Surface

• Mass wasting
• large amounts of material are carried downhill by
  gravity
• rock slides

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External Processes Break Down Earths Surface

• Glaciers
• solid, dense ice
• moves downhill, carving as it goes
• carries material (leaves moraines)

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External Processes Break Down Earths Surface

• Human Activities
• clearing land and vegetation
• over grazing
• mining
• off-road vehicles

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Rock Types Igneous

• Rocks formed by molten rock (magma)
• made at plate boundaries
• below surface - intrusive
• Large crystals
• e.g.. granite
• above ground - extrusive
• lava, no crystals
• e.g.. obsidian, pumice
• Porphyritic both in. and ex.

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• TYPES OF MAGMA
• FELSIC - LIGHT IN COLOR, MAINLY MADE OF FELDSPAR
  AND SILCA SiO2 , FLOW IS SLOW AND THICK,
• EX GRANITE,
• MAFIC - DARK IN COLOR, HIGHER OF IRON,
  MAGNESIUM AND CALCIUM, FERROMAGNESIAM, LOWER IN
  SILCA, FLOW IS FASTER AND THINNER
• EX BASALT
• IGNEOUS ROCKS ARE CLASSIFIED BY
• 1. TEXTURE - SIZE OF THE CRYSTALS
• COARSE-GRAINED, FINE-GRAINED, GLASSY
• 2. TYPE OF MAGMA - FELSIC OR MAFIC

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Types of Igneous rocks FELSIC GRANITE, OBSIDIAN
- ( dark but still felsic ) PUMICE-(floats)
RYOLITE MAFIC GABRO, BASALT, SOCRIA( DOES NOT
FLOAT BECAUSE IT IS DENSER THAN PUMICE)
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Rock Types Sedimentary

• Rocks formed from sediments, other rocks
• A. small rocks carried by water
• sandstone/shale
• B. compaction of dead animals
• limestone
• C. decomposition of plants
• coal
• 3/4 of Earths surface

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• KINDS OF SEDIMENTARY ROCKS
• CLASTIC - FORMED FROM FRAGMENTS OF ROCKS THAT
  ARE CEMENTED TOGETHER - sandstone, shale,
  conglomerate
• DEPOSITION OF SEDIMENTS PLAYS A MAJOR ROLE IN THE
  TYPE OF CLASTIC ROCKS
• CHEMICAL OR PRECIPITATE - fallen out of a
  solution - rock salt, some limestone, gypsum
• ORGANIC - forms from the remains of plants and
  animals - coal or shell limestone
• Stratification

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Rock Types Metamorphic

• Rock formed when a pre-existing rock is subjected
  to extreme heat, chemicals and/or pressure
• e.g.. marble, talc, graphite, slate, gneiss,
  schist
• Foliation layers or nonfoliated

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The Rock Cycle
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Mineral Resources

• Minerals naturally occurring materials in or on
  the crust that can be extracted and converted
  into useful materials
• within the scale of human activities they are
  nonrenewable because of the slowness of the rock
  cycle
• energy resources coal, oil, uranium
• metallic resources iron, copper
• nonmetallic salt, clay, water, sand

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Categories of Mineral Resources

• Identified
• known location and quantity

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Categories of Mineral Resources

• Undiscovered
• believed to exist, but location unknown

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Categories of Mineral Resources

• Reserves
• identified resources that can be extracted
  economically

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Categories of Mineral Resources

• Other Resources
• identified, but not economical, and undiscovered
• may become reserves

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SOIL
The nation that destroys its soil destroys
itself - F.D.R.
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Renewable or nonrenewable?

• Soil is created at a rate of 10 tons per hectare
  (2.5 acres) per year under the best conditions
• Under poor conditions, it can take thousands of
  years to form that much soil
• Soil is created by natural processes, but we are
  depleting it at a faster rate than it can be
  created

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Formation of soils

• Soils are formed from weathering biological
  (plants and fungi), chemical (oxidation), and
  physical (wind, water)
• They are enriched by organic material from plants
  and animals
• The rate at which soil is made is determined by
  the temperature, the amount of soil organisms and
  biotic community

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Major Characteristics of Soil

• Soil Composition
• Particle Size
• Soil Texture
• Organisms
• Soil Horizons

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Soil Composition

• Soils are made of
• particles
• gravel (2-64mm) sand (.05-2mm) silt (.002-.05mm)
  and clay (less than .002mm)
• minerals
• organic material - humus (sticky brown residue
  from partially decomposed plants and animals)
• humus creates structure -how particles cling
  together
• humus holds minerals in soil

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Particle Size

• Particle size determines the amount of air and
  water that is contained in a soil

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Soil Texture
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Properties of Soil Types
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Soil Organisms

• The soil organisms are responsible for breaking
  down the organic material
• Algae live on the surface
• Fungi and bacteria are in the top few cms.
• One half teaspoon can contain hundreds of
  millions of cells
• bacteria fix nitrogen in the soil
• worms and insects add and cycle nutrients in the
  soil

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Soil Horizons
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Types of Soils Desert
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Types of Soils grassland
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Types of Soils tropical rain forest
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Types of Soils deciduous forest
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Types of Soils coniferous forest
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Soil Erosion

• Soil erosion the movement of topsoil and leaf
  litter from one place to another
• Caused by wind and air
• Although erosion is normal, plants normally
  anchor topsoil
• logging, farming, grazing, burning an off-road
  vehicles are causing rapid erosion

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Types of Erosion

• Sheet erosion
• surface water moves down a slope thin uniform
  sheets of soil are removed
• Rill erosion
• little rivulets gather to cut small channels
• Gully erosion
• water forms channels and ravines
• Streambank erosion
• washing away of soil from the banks of a river
• results from tree removal and cattle damage

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Rill and Sheet Erosion
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Gully Erosion
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Global soil erosion
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Desertification

• Denuding and degrading land inducing a
  desert-producing cycle
• productive potential of arid or semiarid land
  falls by 10 or more (more than 50)
• Things leading to desertification
• overgrazing of rangelands
• deforestation
• surface mining
• soil compaction
• salt buildup and waterlogging

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Desertification
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Salinization and Waterlogging

• Water contains dissolved salts
• When water evaporates, the salts are left behind
• Soil salt levels increase
• Farmers apply large amounts of water in order to
  leach salts deeper into the soil
• Roots are saturated with water, killing plants

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Soil Conservation

• Contour plowing
• plowing across the field instead of up and down
• Strip farming
• planting different types of crops in rows (only
  one is harvested and other maintains soil
• Terracing
• shaping land to make flat shelves to hold water
• Alley cropping
• a form of intercropping where trees that can
  provide shade and nutrients for crops

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Contour planting and strip cropping
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Terracing