Earth Science Exam 1 Outline I Introduction A Science state of knowing 1 scientific process and critical thinking The process depends both on making careful observations of phenomena and coming up with explanations for making sense out of those observations 2 observation descriptive statements about natural phenomena that are directly accessible to the senses and about which several observers can agree upon with ease Vs inference statements about natural phenomena that are NOT directly accessible to the senses 3 theories explain how nature works B Earth is a closed system collection of independent parts 1 hydrosphere 2 atmosphere thin envelope of gases that surround the earth 3 biosphere contains all of the planet s living organisms form the ocean floor upward to several kilometers into the 4 lithosphere upper portion of mantle and crust II Structure of the Earth Earth is like an egg A inner core hot solid material 10 000C hotter than the sun B outer core molten liquid layer of earth conducts electricity rotation of earth magnetic field C mantle largest layer of earth 1 lower mantle 2200 degree Celsius 2 upper mantle 870 degree Celsius D crust oceanic crust continental crust III Continental Drift Theory Alfred Wegener A Hypothesis Pangea B Evidence to support his hypothesis 1 Continental Jigsaw Puzzle 2 Fossil Evidence 3 Geographic structures 4 Ancient Climates IV Plate Tectonics Earths crust is made up of plates A Plate Boundaries 1 Divergent boundaries and features constructive margins new crust is generated as the plates pull away from each other form mid oceanic ridges through seafloor spreading 2 Convergent boundaries destructive margins crust is destroyed as one plate dives under another subduction zones deep ocean trenches 3 Transform boundaries conservative margins crust is neither produced nor destroyed as the plates slide horizontally past each other Types of Convergent Boundaries a oceanic oceanic b cceanic continental c continental continental B Hot SpotsHawaiian Island chain C Evidence of plate tectonics ACTIVITY 1 Sea Floor Age 2 Volcanism 3 Earthquakes 4 Seafloor density 5 Seafloor topography D Models of Plate Mantle Convection 1 Layering Layer Cake 2 Whole Mantle Convection E Forces that drive plate movement 1 slab pull sinking of a cold dense slab lithosphere 2 ridge push gravity driven force that results from elevated position of the edge 3 slab suction of oceanic plate start to peel away because it s oldest coldest and dense V Earthquakes A Definition and Terms 1 Earthquake vibration of the earth produced by a rapid release of energy 2 Focus Energy radiates from its source in all directions 3 Epicenter the location on the surface directly above the focus 4 Foreshock small earthquakes that precede major earthquakes used in predicting major earthquakes 5 Aftershock smaller earthquakes after major quake weaker but can cuase much damage on weakened structures B Causes of Earthquakes 1 Elastic Rebound and steps that lead to earthquakes C Rock Deformation Changes in the original shape and or size of a rock body Caused by stress Occurs along plate boundaries 1 Types of rock stress a tensional stretches rock b compressional squeezes rock c shear slippage and translation d confining stress equal from all directions 2 Types of deformation a elastic reversible b ductile change in size shape without fracturing In depth where temperature and preassure are high Results in folds in rocks c brittle Rocks near the surface at low temps and pressure behave like a brittle solid and fracture once their strength is exceeded D Faults ractures in the crust where displacement has occurred generally through brittle deformation 1 Dip Slip Faults aults where the movement is primarily parallel to the inclination or dip in the fault surface a Normal Where the hanging wall block moves down in relation to the footwall block fault b Reverse where the hanging wall block moves up in relation to the footwall block fault Angle of dip is 45o or greater c Thrust where the hanging wall block moves up in relation to the footwall block fault Folding occurs causing shortening and thickening Angle of dip is less than 45o angle 2 Strike Slip Fault Faults where the displacement is horizontal and parallel to the strike of the fault surface Two Types Right Lateral and Left Lateral E Seismic Waves 1 Body Waves 2 Surface Waves a primary waves p waves travel the fastest and thereby felt first b secondary waves s waves slower more destructive a Love waves This one is sort of a Rayleigh Wave on its side b Raleigh waves combination of both p s wave ex Ocean wave F Measuring Earthquakes 1 Seismographs is a device that scientists use to measure earthquakes And they work accurately record the motion of the ground during a quake 2 Locating the epicenter cause that much damage and s waves move slower but more effective a differences in arrivals of p waves move really fast but don t 3 Intensity a Modified Mercalli Scale Invented by Giuseppe Mercalli in 1902 Based on the effects of the quake This scale uses the observations of the people who experienced the earthquake to estimate its intensity 4 Magnitude a Richter Scale InventedbyCharlesF Richterin1934 The Richter magnitude is calculated from the amplitude of the largest seismic wave recorded for the earthquake no matter what type of wave was the strongest Magnitude based on amount of energy released b Moment Magnitude enables seismologists to compare the energy released by different earthquakes on the basis of the area of the geological fault that ruptured in the quake G Destruction Caused by Earthquakes 1 Vibration of Earth s Surface Causes Structural Damage Structures a Intensity of vibration b Duration of vibration c Type of material the structure is on for example 1 Liquifaction Soils containing water turn into a fluid when shake d The design of the structures 2 Tsunamis a differences between Tsunami are caused by undersea earthquake that occurs in a tectonic plate far out to sea on the ocean floorand general ocean waves are caused by tidal movement of the oceans which is regulated by the movement of the Moon and it s proximity to the Earth 3 Landslides 4 fires All material we have discussed in class is fair game for the test There may be material not included in the outline that could be on test