Natural Disasters Energy Sources and Earth’s StructureNatural Processes or Natural Disasters?Energy Sources for Natural DisasterOrigin of the Solar SystemThe Solar SystemSolar EnergyThe Hydrologic CycleUneven Distribution of Solar Energy Causes Severe WeatherEarth’s Internal HeatDensity Differentiation of the Earth Produces Earth’s Internal StructureEarth StructureEarth Structure Density Stratified LayersSlide 13Slide 14Slide 15Earth Structure Layers of Different StrengthsPlate Tectonic TheoryMantle Convection Drives Plate MotionPlate VelocityTypes of Plate BoundariesMoving plates cause EQ’s and volcanoes!Slide 22Natural Disasters Energy Sources and Earth’s Structure•Earths’ Energy Sources•Earth’s Internal Structure•Introduction to Plate TectonicsNatural Processes or Natural Disasters?•The earth is a dynamic planet with complex internal and external flows of energy that produce natural processes that are supposed to happen and have been for billions of years.•Natural disasters occur when the earth’s natural processes concentrate energy and then release it, causing property damage and/or loss of life.Energy Sources for Natural Disaster•Solar Energy•Earth’s Internal HeatOrigin of the Solar SystemA. Rotating cloud of dust and gas gathers due to gravitational forces.B. Rotating mass contracts and flattens with most of the mass in the center. D. Accretion results in planet formation whereby the gases outside of the sun condense into solid materials.C. The center contracts into a ball of hot gas and dust which ignites to form the sun.The Solar SystemSolar EnergyThe Sun is the Power House for the entire Solar System. It is a fairly typical star that is not burning, but is fusing together Hydrogen to form Helium. In so doing, it releases energy in vast quantities. Fusion of Hydrogen into HeliumThe Hydrologic CycleUneven Distribution of Solar Energy Causes Severe WeatherEarth’s Internal HeatThree Sources of the Earth’s Internal Energy (Heat)•Gravitational collapse•Impact Energy•Radioactive decayEnd Result…Early Earth is hot, hot, hot!!!Density Differentiation of the Earth Produces Earth’s Internal Structure•Crust•Mantle•Outer core•Inner coreRefer to pages 17 – 21Earth StructureThe earth today is the product of over 4.5 billion years of differentiation into layers of varying density.The 8 most abundant elements in the earth are •oxygen (O), •silicon (Si), •iron (Fe), •magnesium (Mg), •sodium (Na), •calcium (Ca), •aluminum (Al) and •potassium (K)Earth Structure Density Stratified LayersEarth’s Core•The earth’s core is composed of two parts, the inner core and the outer core.•The inner core is SOLID iron (Fe) and nickel (Ni) and the outer core is LIQUID Fe and Ni.Refer to pages 17 – 21Earth Structure Density Stratified LayersMantle•The mantle extends from roughly 50-2900km below the earth’s surface and is primarily composed of Fe, Mg rich silicates minerals.Refer to pages 17 – 21Earth Structure Density Stratified LayersCrustIs composed of two types:•Oceanic Crust is 7-10 km thick primarily made of Fe and Mg rich silicate minerals. (MAFIC; low Si and O, high Fe and Mg)•Continental Crust is 20-70km thick primarily made of Si and O rich minerals (FELSIC; high Si and O, low Fe and Mg)Refer to pages 17 – 21Earth Structure Density Stratified LayersDensity = mass/volumeIn General, density can be changed by changing either the pressure or temperature.Crust vs. MantleThe mantle contains MORE Fe and Mg than the oceanic crust and the oceanic crust contains MORE Fe and Mg than the continental crust.Because Fe and Mg are DENSER elements, the mantle is denser than the oceanic crust and the oceanic crust is denser than the continental crust.Earth Structure Layers of Different StrengthsThe crust and the upper part of the mantle is called the LITHOSPHERE and it is RIGID, BRITTLE and behaves ELASTICALLY.The part of the mantle directly below the lithosphere is termed the ASTHENOSPHERE which behaves like a PLASTIC - a solid that flows. Refer to pages 17 – 21Plate Tectonic Theory12 large plates (e.g., Pacific Plate), 12 small plates (e.g., Arabian Plate)Refer to pages 15 – 21Mantle Convection Drives Plate MotionHeat Sources•Original heat from formation of the Earth•Radioactive decay of U, Th, and K in the core and mantlePlate Velocity Up to ~17 cm/yrTypes of Plate BoundariesRefer to pages 20 - 21Moving plates cause EQ’s and volcanoes!Refer to pages 20 - 21Moving plates cause EQ’s and volcanoes!Refer to pages 20 -
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