Plate Tectonics and EarthquakesPlate Tectonics and EarthquakesPlate Tectonics and EarthquakesPlate Tectonics and EarthquakesObjectives:Objectives:
• Students will learn key terms associated withStudents will learn key terms associated with plate tectonic processes. (Part A)plate tectonic processes. (Part A)
• Students will understand the specific plateStudents will understand the specific plate motions associated with divergent, motions associated with divergent, convergent, and transform plate boundaries.convergent, and transform plate boundaries. (Part B)(Part B)
• Students will gain a global view of EQ’sStudents will gain a global view of EQ’s (where EQ’s typically occur). (Part C)(where EQ’s typically occur). (Part C)
• Students will evaluate and apply conceptsStudents will evaluate and apply concepts from lab parts A, B, and C to answer criticalfrom lab parts A, B, and C to answer critical thinking questions. (Part D)thinking questions. (Part D)
Objectives:Objectives:
• Students will learn key terms associated withStudents will learn key terms associated with plate tectonic processes. (Part A)plate tectonic processes. (Part A)
• Students will understand the specific plateStudents will understand the specific plate motions associated with divergent, motions associated with divergent, convergent, and transform plate boundaries.convergent, and transform plate boundaries. (Part B)(Part B)
• Students will gain a global view of EQ’sStudents will gain a global view of EQ’s (where EQ’s typically occur). (Part C)(where EQ’s typically occur). (Part C)
• Students will evaluate and apply conceptsStudents will evaluate and apply concepts from lab parts A, B, and C to answer criticalfrom lab parts A, B, and C to answer critical thinking questions. (Part D)thinking questions. (Part D)
Continental Drift vs. Plate Tectonics – The DebateContinental Drift vs. Plate Tectonics – The Debate
Alfred WegenerAlfred Wegener
1912- observed thepossible fit betweenSo. America and Africa.
1912- observed thepossible fit betweenSo. America and Africa.
• Hypothesized the continents were all together forming the supercontinent Pangaea – 250 million years ago
• Supported by the following evidence:
• fossil evidence• lithologic evidence• climatic evidence
• Hypothesized the continents were all together forming the supercontinent Pangaea – 250 million years ago
• Supported by the following evidence:
• fossil evidence• lithologic evidence• climatic evidence
Wegener became the laughing stalkof the science world – WHY?
Wegener became the laughing stalkof the science world – WHY?PangaeaPangaea
Continental Drift vs. Plate Tectonics – The DebateContinental Drift vs. Plate Tectonics – The DebateMid-Atlantic Ridge
• 1947 – mapping of the ridge• linear mountain range
• active EQ and volcanism
• area of sea floor spreading
Mid-Atlantic Ridge• 1947 – mapping of the ridge
• linear mountain range
• active EQ and volcanism
• area of sea floor spreading
Sea Floor Spreading• Magma rises in between the ocean floor (ridge).
• Magma pushes the ocean floor – spreading the floor apart.
Sea Floor Spreading• Magma rises in between the ocean floor (ridge).
• Magma pushes the ocean floor – spreading the floor apart.
Can scientists actually see “spreading” of the ocean floor?How do scientists know the floor is actually moving?Can scientists actually see “spreading” of the ocean floor?How do scientists know the floor is actually moving?
PaleomagnetismPaleomagnetism --- the evidence that the sea floor is active --- the evidence that the sea floor is active and moving (by the late 1960’s)and moving (by the late 1960’s)PaleomagnetismPaleomagnetism --- the evidence that the sea floor is active --- the evidence that the sea floor is active and moving (by the late 1960’s)and moving (by the late 1960’s)
PaleomagnetismPaleomagnetism: : paleopaleo (past) (past) magnetismmagnetism (magnetic) (magnetic)• past magnetism of lava flows are past magnetism of lava flows are recorded on recorded on the sea floorthe sea floor
• Iron in magma will point to the Iron in magma will point to the current current north pole. Evidence shows north north pole. Evidence shows north pole pole switches location to the south pole switches location to the south pole over over geologic time (magnetic reversals).geologic time (magnetic reversals).
PaleomagnetismPaleomagnetism: : paleopaleo (past) (past) magnetismmagnetism (magnetic) (magnetic)• past magnetism of lava flows are past magnetism of lava flows are recorded on recorded on the sea floorthe sea floor
• Iron in magma will point to the Iron in magma will point to the current current north pole. Evidence shows north north pole. Evidence shows north pole pole switches location to the south pole switches location to the south pole over over geologic time (magnetic reversals).geologic time (magnetic reversals).
North reversalNorth reversalNorth reversalNorth reversal South reversalSouth reversalSouth reversalSouth reversalcreating magnetic reversals on bothcreating magnetic reversals on bothsides of the plate (pattern of stripes)sides of the plate (pattern of stripes)creating magnetic reversals on bothcreating magnetic reversals on bothsides of the plate (pattern of stripes)sides of the plate (pattern of stripes)
magnetic patternmagnetic pattern 13
The Plate Tectonic ModelThe Plate Tectonic Model
• The plate tectonic model describes surface features, geologic environments, and patterns of EQ’s and volcanism.
• Ridgid lithospheric plates (continents + ocean floor) ride along the soft layer (like hot wax) called the asthenosphere
• Plates spread apart, collide, and slide past one another.
• EQ’s, crustal deformation, and volcanism take place at plate boundaries.
• The plate tectonic model describes surface features, geologic environments, and patterns of EQ’s and volcanism.
• Ridgid lithospheric plates (continents + ocean floor) ride along the soft layer (like hot wax) called the asthenosphere
• Plates spread apart, collide, and slide past one another.
• EQ’s, crustal deformation, and volcanism take place at plate boundaries.
EarthquakePatterns
VolcanismPatterns
lithospherelithosphere
Asthenosphere (upper mantle)Asthenosphere (upper mantle)
Plate BoundariesPlate BoundariesPlate BoundariesPlate Boundaries
Divergent Boundary – plates move AWAY from each otherDivergent Boundary – plates move AWAY from each other
Convergent Boundary – plates move TOWARD each otherConvergent Boundary – plates move TOWARD each other
Transform Boundary – plates SLIDE past each otherTransform Boundary – plates SLIDE past each other
Divergent Boundary:Divergent Boundary:
• plate material separatingplate material separating
Divergent Boundary:Divergent Boundary:
• plate material separatingplate material separating
ocean plate divergence Extensional forcescreate EQ’s
continental divergence
Extension createsfaulting
• Earthquake activity• Earthquake activity
Ocean-ContOcean-ContOcean-ContOcean-Cont Ocean-OceanOcean-OceanOcean-OceanOcean-Ocean Cont-ContCont-ContCont-ContCont-Cont
Convergent Boundary:Convergent Boundary:• interaction of two plates moving toward one anotherinteraction of two plates moving toward one another making contact– hence, collision or convergencemaking contact– hence, collision or convergence
• collisions produce earthquakes, volcanic activity, andcollisions produce earthquakes, volcanic activity, and crustal deformationcrustal deformation
Convergent Boundary:Convergent Boundary:• interaction of two plates moving toward one anotherinteraction of two plates moving toward one another making contact– hence, collision or convergencemaking contact– hence, collision or convergence
• collisions produce earthquakes, volcanic activity, andcollisions produce earthquakes, volcanic activity, and crustal deformationcrustal deformation
Subduction zone
Subduction zone SubductioinSubductioin
zonezoneSubductioinSubductioin
zonezoneOregon-Washington
CoastOregon-Washington
CoastAleutian Island(Alaska area)
Aleutian Island(Alaska area)
Himalayan MountainsHimalayan Mountains
ocean-continentocean-continent
ocean-oceanocean-ocean
cont-contcont-cont
• thinner and more dense platethinner and more dense plate subductssubducts• subducted plates melt (160 km)subducted plates melt (160 km) below the surface, and magmabelow the surface, and magma risesrises• EQ’s occur along the subductionEQ’s occur along the subduction zone, and magma plumes risezone, and magma plumes rise
• thinner and more dense platethinner and more dense plate subductssubducts• subducted plates melt (160 km)subducted plates melt (160 km) below the surface, and magmabelow the surface, and magma risesrises• EQ’s occur along the subductionEQ’s occur along the subduction zone, and magma plumes risezone, and magma plumes rise
• typically, the older plate will typically, the older plate will subduct (more dense) beneath subduct (more dense) beneath younger plate materialyounger plate material
• melting plate material rises,melting plate material rises, creating volcanic arc systemscreating volcanic arc systems
• most EQ’s occur within themost EQ’s occur within the subduction zonesubduction zone
• typically, the older plate will typically, the older plate will subduct (more dense) beneath subduct (more dense) beneath younger plate materialyounger plate material
• melting plate material rises,melting plate material rises, creating volcanic arc systemscreating volcanic arc systems
• most EQ’s occur within themost EQ’s occur within the subduction zonesubduction zone
• two plates converge with thetwo plates converge with the same densitysame density
• same density prevents same density prevents subductionsubduction
• extensive deformationextensive deformation
• two plates converge with thetwo plates converge with the same densitysame density
• same density prevents same density prevents subductionsubduction
• extensive deformationextensive deformation
• Earthquake activity• Earthquake activity
Transform Boundary:• two plates are sliding past one another
• lack the spectacular features associated with divergent/convergent boundaries
• marked by linear valleys (slices through the earth’s crust)
• shallow-focused EQ’s occur along the slip area of the sliding plates
Transform Boundary:• two plates are sliding past one another
• lack the spectacular features associated with divergent/convergent boundaries
• marked by linear valleys (slices through the earth’s crust)
• shallow-focused EQ’s occur along the slip area of the sliding plates
SAFSAF
Transform boundaries offsettingspreading ridges
• Typical EQ’s occur along the transform boundary.
Transform boundaries offsettingspreading ridges
• Typical EQ’s occur along the transform boundary. EarthquakesEarthquakes
Cross-sectional view of the SAFand associated LA faults
•SAF – transform motion•LA faults- vertical motion
Cross-sectional view of the SAFand associated LA faults
•SAF – transform motion•LA faults- vertical motion SAF-transform faultSAF-transform fault
Los AngelesLos Angeles
What moves or drives the plates?What could Wegener have told the geological society? What moves or drives the plates?What could Wegener have told the geological society?
Only a Model – Think Only a Model – Think ConvectionConvectionOnly a Model – Think Only a Model – Think ConvectionConvection
Convection – heat transfer through a liquid or gas that results in circular movement of particles
Convection – heat transfer through a liquid or gas that results in circular movement of particles
Hot water risesHot water rises
Cooler water sinksCooler water sinks
RiseRise
FallFall
Earth CrustEarth Crust
mantlemantlemantlemantle
The Earth’s MantleThe Earth’s MantleCan you see the convection?Can you see the convection?
Mantle operates like a “lava lamp,” producingMantle operates like a “lava lamp,” producingswelling and shrinking of magma plumes.swelling and shrinking of magma plumes.
Mantle operates like a “lava lamp,” producingMantle operates like a “lava lamp,” producingswelling and shrinking of magma plumes.swelling and shrinking of magma plumes.
Earth’s Surface
Earth’s Surface
57
Latitude and Longitude• Where are you on earth?Latitude and Longitude• Where are you on earth?
Latitude/Longitude• a grid system used to locate features on the earth’s surface
Latitude/Longitude• a grid system used to locate features on the earth’s surface
Latitude: • parallel lines that move north
and south
Latitude: • parallel lines that move north
and south• 0o latitude = equator• 0o latitude = equator
Longitude:• meridian lines that move east and west
Longitude:• meridian lines that move east and west • 0o longitude is through Greenwich, England• 0o longitude is through Greenwich, England 11
Los Angeles, Ca 350 N-lat, 1210 W-longLos Angeles, Ca 350 N-lat, 1210 W-longSpokane, Wa 470 N-lat, 1180 W-longSpokane, Wa 470 N-lat, 1180 W-longNew York, NY 420 N-lat, 750 W-longNew York, NY 420 N-lat, 750 W-long 12
Latitude (+)Longitude (-)Latitude (+)
Longitude (-)
Latitude (-)Longitude (-)Latitude (-)
Longitude (-)
EastWest
North
South
Latitude (+)Longitude (+)Latitude (+)
Longitude (+)
Equator
Prim
e Merid
ianLatitude (Latitude (-)Longitude (+)
Latitude (-)Longitude (+)
A
B
C
DE
15 N-lat, -132 W-long15 N-lat, -132 W-long
52 N-lat, 78 E long52 N-lat, 78 E long
-18 S-lat, -162 W-long-18 S-lat, -162 W-long-55 S-lat, -15 W-long-55 S-lat, -15 W-long
-25 S-lat, 136 E long-25 S-lat, 136 E long
13
Plate Tectonics Lab:
• Part A: Plate tectonic definitions• use lab text• use textbook resources in classroom
• Part B: Identification of plate boundaries• use lab text, colored pencils• use textbook resources in classroom
• Part C: Plotting EQ location• use provided long/lat handouts• use colored pencils
• Part D: Critical thinking questions• use parts A, B, and C and your synthesizing brain.
Plate Tectonics Lab:
• Part A: Plate tectonic definitions• use lab text• use textbook resources in classroom
• Part B: Identification of plate boundaries• use lab text, colored pencils• use textbook resources in classroom
• Part C: Plotting EQ location• use provided long/lat handouts• use colored pencils
• Part D: Critical thinking questions• use parts A, B, and C and your synthesizing brain.