Review sheet for test 4 Be sure to review notes, text book and compose your own notes and outlines. Review and learn terms/word and how they apply. The following is a list of topics – it may or may not be complete and is not all –inclusive. Please be sure to completely research eachtopic and understand the processes described in the text and in lecture.Good luckEarthquakesEpicenter, focus, fault • FOCUS – the point within the earth where the rupture occurs• EPICENTER – point on the earth’s surface directly above Focus• FAULT PLANE – where rock movement occurs• Faults can expand at velocities up to 7200 mph!Elastic-rebound• Strain (energy) builds up in rocks• Rocks deform• Strain exceeds rock strength > Rocks break• Rocks “snap back” to original, undeformed position– The Rapid return to original shape (Rebound), releases energyForeshocks; aftershocksRelationship of earthquakes to plate tectonics• Plate tectonics - the constant shifting of earth’s crusts allow rocks to deform or behave elastically• Rocks elastically deform until the strength of the rocks is exceeded, and then they break• The breakage (and rebound) of rocks transmits energyEarthquake depth and plate tectonics• No earthquakes occur below 450 miles from the surface. Why?• 90% of all earthquakes occur within 60 miles (~100 km) of the surface (Shallow FOCUS)• Almost ALL catastrophic earthquakes occur within 40 (~60 km) miles of the surface• Shallow Focus earthquakes are associated with Divergent or Transform Plate boundaries• Shallow, Intermediate or Deep Focus earthquakes can occur at Convergent BoundariesBody waves (p and s wave)• Body Waves – Travel through earth• P-Wave (Primary Waves)• Fastest wave (4 miles/second)• Travel by compression• Can travel through Solids, Liquids and Air• Occur as a jolt when they intersect the surface• S-Wave (Secondary wave)• Slower than p-waves (2 miles/second• Shear Motion• Travel only through solids• Occur as jerking motion when they reach earth surfaceSurface wave (Rayleigh and Love)• Surface Waves – travel on surface; larger than body waves, but travel slower (1.5miles/second)– Surface waves: originate when body waves travel to the epicenter, where they cause the earth’s surface to vibrate• Rayleigh• Love wavesSeismograph stations; seismograms- Seismographs – Stations that record the passage of seismic waves- Seismogram - the record of passing seismic wavesRichter scale- Measures Magnitude of energy released- Scale from 1 – 10- Measures the magnitude of energy- It is a Log scale system- Each 1 whole unit represents a 10-fold increase in Magnitude, but a 30-fold increase in the amount of Energy released for each whole unit increase!- Magnitude, then, is based upon the amplitude of the seismic waveMercalli scale- Measures Intensity of shaking by assessing the damages- Scale from I to XIIAmount of energy and wave amplitude released between magnitudes• An earthquake of M 7 has 10 times the amplitude of an earthquake of M 6, and 30times more energy• An earthquake of M 7 has 100 times the amplitude of an earthquake of M 5, and 900 times more energy• An earthquake of M 7 has 1000 times the amplitude of an earthquake of M 4, and 27000 times more energyHazards• Earthquakes pose a significant factor killing thousands each year– Primary effect is ground motion– Ground motion may cause additional indirect damage by• Displacement• Landslides• Liquefaction of soil-Unconsolidated sediments can behave as a liquid when seismic waves pass• Fires from broken gas pipes• Tsunamis• Large Amplitude and long wave-length ocean waves causedby displacement of water• Can reach heights of 100 feet; Can travel at velocities of 500 mph!• Seafloor fault movementPredicting earthquakes• Seismic Risk maps• Changes in land forms• Seismic Gaps• Fluctuations of water table• Released gases• Animal BehaviorReducing damagesHazard mapsSeismic gaps-sections along a fault line that have not experience any recent seismic activitySeismic waves and earth’s interiorProperties and behavior of P and S waves as they travel through different materialsP-waves travel through solids, liquids, and gases (faster through solids, slower through liquids)S-waves- travel only through solids Where shallow, medium depth and deep foci earthquakes occur and whyReflection and refraction- Waves can Reflect when they encounter another layer of material- Waves can Refract (Bend) when travelling Through different layersThe effect of density and temperature on seismic wave velocityS- and P-wave shadow zones; how the form and where (in relation to focus)Oceanic crust versus continental crust as observed by seismic wavesAsthenosphere, mantleInterpreting earth’s interior:Radius of planet, depth to mantle, outer core, inner core- Earth’s total radius from core to crust = 6370 kmComposition of internal parts and why seismic waves are able to provide us this informationVelocity of Seismic waves increases with increasing densityVelocity also Decreases when materials increase in temperatureMoho: Crust- Mantle boundary• Mohorovicic Discontinuity (Moho)– First discovered by Andrija Mohorovicic– Occurs between 5 and 70 km deep– Represents the base of the crust– Compositional change from feldspar rich to olivine rich causes change in seismic velocities (increased velocities in the mantle)Evidence for outer and inner core, evidence for their compositionCause of magnetic fieldRotating Metallic material= Magnetic fieldSeismic tomography• Seismic wave velocity also dependent upon temperature of materials• Observe possible plate tectonic interactions• Observe possible heat convectionApplication of seismic techniques• Oil exploration• Assessing volcanoes• Locating various rock layers, pollution, resourcesClimate:AtmosphereTroposhere, stratosphere; mesosphere, thermosphereAtmospheric gas compositionGreenhouse gases-CO2, Methane, Water Vapor and other compounds• The greenhouse effect • Radiant energy that is absorbed heats Earth and eventually is reradiated skyward.CO2 concentration in atmosphereShort wave to longer wavelength conversionAlbedoMilankovich cycles• Variations ins earths orbital parameters• Eccentricity of Orbit around sun– 100,00 year cycles• Axial Tilt– 41,000 year cycles• Precession– 23,000 year cyclesThermohaline currentsConvection cellsCoriolis effectClimate zones1.