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80 Cards in this Set
- Front
- Back
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The Theory of Plate tectonics started _____
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A revolution in the Earth Sciences
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What is a Plate?
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A large, rigid slab of solid rock
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Tectonics Root words
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Greek root to build
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Theory of Plate Tectonics
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states that the Earth's outermost later is gragmented into a dozen or more large and small plates that are moving relative to one another as they ride atop hotter, more mobile material.
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When did Pangaea begin to break up?
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225-200 million years ago
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Plate tectonics is a relatively new scientific concept, introduced __ years ago
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30
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James Hutton Proposed the ____ Principle in 1785
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Uniformitarian Principle
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Uniformitarian Principle
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The present is the key to the past.
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Abraham Ortelius
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Dutch map maker in 1596 that suggested the Americas were torn away from Europe and Africa
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Alfred Lothar Wegener
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German meterologist that stated 200 million years ago the super continent Pangea bega to split apart (Continental Drift)
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2/3 of the Earth's surface lies beneath ___
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Oceans
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Sea Floor Spreading
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New magma from deep within the Earth rises easily through the weak zones and eventually erupts along the rest of the ridges to create new oceanic crust
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Harry H. Hess
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Princeton University geologist who first coined the term seafloor spreading
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Earthquake- recording instrument
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seismograph
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Four types of Plate boundaries
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Divergent boundaries
Convergent Boundaries Transform Boundaries Plate boundary zones |
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Divergent boundaries
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where new crust is generated as the plates pull away from each other
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Convergent Boundaries
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where new crust is destroyed as one plate dives under another
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Transform boundaries
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where crust is neither produced nor destroyed as the plates slide horizontally past each other
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Plate Boundary Zones
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broad belts in which boundaries are not well defined and the effects of plate interaction are unclear
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Mid-Atlantic Ridge are
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divergent boundaries that are a submerged mountain range extending from the Arctic Ocean to the Southern tip of Africa
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The rate of Spreading along the Mid-Atlantic Ridge
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2.5 centimeters per year
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Crust must be destroyed at about the ___ rate as it is being created
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Same
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The location where sinking of a plate occurs
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Subduction Zone
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Convergence can only occur between..
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1) an oceanic and a largely continental plate 2) two largely oceanic plates 3) two largely continental plates
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Trenches are the ___ parts of the ocean floor and are created by ___.
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deepest, subduction
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World's Tallest Mountain
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Mount Everest
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The ring of fire lines the
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pacific coast and East Asia and Australia
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Subduction process in oceanic-oceanic plate convergence results in the formation of
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Volcanoes
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Continental- Continental convergence results in
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Mountains
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The zone between two plates sliding horizontally past one another is called
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Transform boundary
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Hot spot theory
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relatively small, long- lasting, and exceptionally hot regions existed below the plates that would provide localized sources of high heat energy (thermal plumes) to sustain volcanism.
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J. Tuzo Wilson is known for
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Hot spot theory
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Suggest the plate-driving force is the slow movement of hot, softened mantle that lies below the rigid plates.
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Arthur Holmes
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Most earthquakes and volcanic eruptions do not strike randomly but occur in specific areas, such as along
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Plate Boundaries
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geographic point directly above the focus
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earthquake epicenter
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rupture point =
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earthquake focus
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San Andreas is a ____ fault
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strike slip
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RAPID shear slip across a Fault surface
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Earthquake
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Seismic Waves
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Mechanical vibrations in the air (P waves and S waves)
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S waves travel through mantle but not the
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outer core
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type of waves used to measure the magnitude of earthquakes
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Seismic
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Faults
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Discontinuity of the rock volume resulting in a space between two rocky slabs of the earth
Movement in a specific geometric configuration |
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Measure of the strength of earthquake’s shake
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Magnitude
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Calculate the _____ of an earthquake by looking at the seismographic record of an earthquake
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Magnitude
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How many earthquakes with magnitude 8+ per year?
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1
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Intensity scale
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Asks people how the felt and what they observed during earthquake
Based off the scale, isoseismal maps are plotted |
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Isoseismal map
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Maps of intensity observations
Show that the intensity decreases and less damage would occur as a result of smaller intensity of the propagation earthquake. |
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Economic damage and injuries begin at what shaking intensity?
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6-7
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Does Earthquake mitigation depend on economic decisions
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yes
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_____ are special mountains where magma errupts and goes to the Earht's surface.
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Volcanoes
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Two types of volcanic eruptions
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Explosive style and Passive Hawaii Style
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What is a volcanic eruption
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They are when the magma erupts to the surface of the earth.
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Shield volcanoes are _____ (Hawaii volcano) and produce ____ rocks.
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Passive eruption, basaltic
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Strato volcanoes (St. Helen) are ____ and produce _____ rocks
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explosive, andesite
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basic structure and composition of the earth
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Composed of layers :
Outer most layer is called the Crust Then Mantle Liquid outer core Solid inner core |
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How does earth make basaltic magma?
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Mid-Ocean ridges
Reasonably hot rocks rise to ocean surface and as pressure decreases Mantle rock melts Continental Volcanoes Adding water to the reasonably hot rock which results in crossing the dry melting curve. |
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Hot spots?
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Where volcanoes occur other than near the Ring of Fire.
Also a source for magma formation for the volcano found on Hawaii islands. |
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hazards caused by volcanic eruptions
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Lahar "hot mud"
Ash Fall Global cooling Pyroclastic flow Lava Flow. |
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3 Ps of mitigation
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Prevention
Prediction Preparation |
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Best mitigation strategy for volcanoes
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Don't build on previous volcanic flows.
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Rock begins to melt
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solidus
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liquidus
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rock is completely molten
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Area on earth where two tectonic plates move towards one another and sinking occurs
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subduction zone
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3 types of plate boundary motions
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divergent
transform convergent (subduction) |
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Divergent
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mid-ocean spreading center: plates move away and magma comes up
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Transform faults
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plates slide past each other
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Convergent/subduction zones
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plates move towards each other-one goes on top of the other
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Slip fault-fault rupture
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nearly vertical & one side slides past the other
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Normal Fault/ dip-slip-Fault
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relative displacement parallel to the dip of the fault plane
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Thrust fault
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where rocks with lower strata position are pushed up&over higher strata
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Blind thrust fault
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if plate terminates before reaching earth's surface
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Ground shakes at max
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1G
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Occur at plate boundaries-mostly at subduction zones
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Earthquakes
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Most of the
“VERY LARGEST” Earthquakes occur In just a ____ of the Subduction Zones |
FEW
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Largest EQ was in
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Chile 9.5
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Japan Earthquake was
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March 11, 2011
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Japan Earthquake magnitude
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9
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Earthquakes Hazardous because
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1)building fall down on us
2) landslides can be triggered 3) Tsunamis can be generated |
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Invention of first seismograph
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1889
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Basalt
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molten rock
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