Presentation on theme: "The interior of the earth and it’s surface"— Presentation transcript:
1The interior of the earth and it’s surface Chapter 9 and 10The interior of the earthand it’s surface
2The Interior of the Earth We can’t go thereUse the shock waves an earthquake makes to investigate it.Called seismic wavesTwo typesS waves (sheer waves)P waves (pressure waves)Measured with a seismograph
7Seismic waves Penetrate earth and return to surface. Speed and direction changeS waves can’t go through liquidsP waves can, but they slow down.As the waves go through the earth at 2900 km down, the S waves stop and the P waves slow downAt 5105 Km down the P waves speed upWhat does this tell us?
8The Earth’s Core The center of the earth Two layers Inner core Iron and Nickel5000º CPressure keeps it solidResponsible for magnetic field?
9The Earth’s Core The outer core Iron and Nickel 2200º C to 5000º C Not as much pressure so it is liquidHow do they knowP waves are pressure wavesWill go through liquidS waves are sheer waveswon’t go through liquids
14The Mantle Above the outer core 80% of the earth’s volume Studied rocks from volcanoesHave studied rocks from the ocean floorSilicon, oxygen, iron, magnesiumDensity increases with depthBecause there’s more ironMeasured by speed of the seismic waves
15The Mantle Temperature increases with depth Has plasticity What is plasticity?A solid that can flow like a liquidSilly putty870º C -2200º C
16The Moho the thin boundary layer between the mantle and the crust 32-64 kmDiscovered by Andrija MohorvičićFound seismic waves changed speed at this levelEither different composition or density.
17The crust Thin outer layer we live on If the earth were the size of an apple, the crust would be thinner than the peel8-32 kmTwo kindsOceanicLess than 10 kmall basalt- dense
18The crust Continental crust Thicker- averages 32 km, up to 70 km Top layer granite- less dense, on top of dense basaltEarth’s crust also called lithosphereLithosphere broken into large plates (called tectonic plates)
22Crust Continental – Thicker Granite and basalt Oceanic Thinner All BasaltStress- the pushes and pulls on the crustcauses changes in the rockShapeVolumeCompresses or expandsDeformation- breaking, tilting, and folding of of rocks
24Stress Three types Compression- pushed together Moves land higher up and deeper
25StressTensionPulled apartStretches like taffyThinner in the middle
26StressTensionPulled apartStretches like taffyThinner in the middle
27Stress Shearing- pushes in two opposite horizontal directions Rocks are torn apart or bent
28Stress Shearing- pushes in two opposite horizontal directions Rocks are torn apart or bent
29Stress changes Shape Volume Density Can cause cracks - fracture Fracture along smooth surface is called a jointJoints are parallel
30Faults A break or crack where rocks move Where earthquakes happen Hanging wall- above the faultFoot wall- below the faultThree types of faulttension causes normal faultCompression causes reverse fault and thrust fault
46Why Fold Why don’t they break Temperature- hot rock is easier to bend Pressure- higher pressure more likely to foldType of rock- some are more brittle, some are more malleableGradual force bends, sudden force breaks
47PlateauFlat area made of layers of flat-topped rocks high above sea levelCan be formed like fault block mountainsOr by lava flows (lava plateau)Colorado plateau- West of the Rocky mountainsformed Grand canyonRivers cut large plateau into several smaller ones
48Domes Magma forms a bubble underneath the crust, without erupting Half sphere surrounded by flat landIf worn into separate peaks they are called dome mountains
49The Crust Floats On the mantle Because it is less dense The floating crust pushes downThe crust pushes up.Balance of forces called isostasyMore material floats lower