Plate Tectonics Flashcards

Terms Definitions
Mrs. Bowman
My cards
Oceanic crust
earths crust located under the ocean
Mid-ocean ridge
An undersea mountain chain where new ocean floor is produced; a divergent plate boundary.
Subduction zone
The region where oceanic plates sink down into the asthenosphere.
Seafloor spreading
The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another, The process that creates new sea floor as plates move away from each other at the mid-ocean ridges
Seismograph
Detects foreshocks
1300
Buildings in Christchurch red-stickered
£17 billion
Phillipine foreign debt
160km
Length of tsunami waves
13km
Depth of Haitian earthquake
7.00am-7.00pm
Curfew in Christchurch CBD
7
Magnitude of Haitian earthquake
800kmph
speed of tsunami waves
2m
Subsidy of Japanese coastline
1220km
radius of Inner core
Phillipine Volcanology and Seismology
PHIVOLCS
USGS
United States Geological Survey
90%
Damaging tsunamis originate Pacific Ring of Fire
2300km
Depth of the outer core
66-75%
Silica content of rhyolitic lava
Sial
Less dense, thick continental plates
6km3
Water displaced by Japanese earthquake
4.6 billion
Age of the Earth
Strombolian
Eruption type small frequent eruptions
Sima
More dense, thin oceanic crust
42-52%
Silica content of basaltic lava
-0.4%
Impact on New Zealand GDP
147
Killed by Mount Nyiragongo eruption
500-9000
Celcius temperature variation within the mantle
Moho Discontinuity
When crust becomes mantle
1380
Previous eruption of Mount Pinatubo
500,000
People displaced by Japanese earthquake
15minutes
Distance of wave to coastline
181
Killed by New Zealand quake
10m
Height of Japanese tsunami waves
Features of Boundaries
volcanoes,saline lakes, fold mountains, trench.
6400km
Approx depth of the inner core
Vulcanian/Vesuvian
Eruption type, more violent than Strombolian but less frequent
Composite
Volcano shape Andesitic lava e.g. Mount St. Helens
Cascades Volcano Observatory
Monitors Mount St. Helens
Icelandic
Eruption type, lava flows from fissure
£30million
Insurance cost of Market Rasen quake
87%
Survivors of Haitian earthquake in refugee camps a year on
91.4%
GeoNet success rate in earthquake prediction
Magnetometer
Measures minor movements in magnetic field
70,000
Kids educated by Volcano and Environmental Risk Management Unit
120km
Distance of epicentre from Japanese coastline
1.5 million
Made homeless by Haitian earthquake
200
Homes destroyed by Mount St. Helens
16
Ambulances operational by St. John within half an hour, then recieving 700 calls in 6 hours
1
Killed in Tokyo from the earthquake
120
Rescued from ruins in New Zealand
$184 billion
Injected into Japanese money market
4.4million
Immediate loss of power in Japan
The Two northern and southern continents in Panaea
Lurasia, Gondwanaland
GeoNet
network of instrument and data centres across New Zealand, operated by Institute of Geological and Nuclear Sciences in New Zealand
$1.4 billion
Cost of reconstruction after Haitian earthquake
Plinian
Eruption type, large amounts of lava and pyroclastic material
12th January 2010, 4.53pm
Earthquake occured in Haiti
March 20th
Earthquake measuring 4.1 occurs near Mount St. Helens
April 1964
Surtsey formed by 130m ash cone
8ft
Mud layer after Mount St. Helens erupts
Acid or Dome
Volcano shape with Rhyolitic lava
680mph
Speed of mud and pyroclastic flows from Mount St. Helens
£2 million
Aid from the International Development Fund for Mount Nyiragongo
8300
Confirmed dead by March 21st after Japanese earthquake
£1 million
UK aid pledged to Mount Nyiragongo
5 years
Estimated time for recovery after Japanese earthquake
March 15th-19th 1980
Earthquakes detected by Mount st. Helens
Tsunami warning Centre
Established Japan 1952, 6 regional centres and 300 sensors.
Tilt meter and creep meter
Monitors minor earth movements
10,000
Homes to be demolished and rebuilt in Christchurch
Phillipine Plate
Plate subducted to form Mount Pinatubo under the Eurasian plate
Francis Bacon
Made the theory of Continental Fit, 1620
Earthquakes at Collision boundary
Shallow earthquakes at low density
16 mile
Collumn of ash from Mount St. Helens
23rd January 1973
Fissure eruption near Icelandic port, Heimay. 2km fissure
8.32am May 18th 1980
Eruption caused by earthquake Mount St. Helens
150,000 and 3,500
Cholera cases and deaths after Haitian earthquake
4000km + 50km
Length and depth of African Rift Valley
9th June 1991
Mount Pinatubo eruptions of steam and ash
CAFOD, Christain Aid and Red Cross
Aid agencies working in Goma
Earthquakes at Constructive boundaries
Mainly shallow and submarine, can also occur at areas of inland crustal tension
Pacific Early Warning System
1948, 24 countries and 30 seismic stations and 70 tidal stations
Great Calafornia Shake Out
Event day in July to practice drills
Minstry of Civil Defence and Engineering Management
Co-ordinated relief in New Zealand
30 million tonnes
Ice fell of Tasman Glacier into lake, creating tsunamis
$1 billion out of $1.5 billion
Aid recieved out of required funds for reconstruction after Haitian earthquake
jerett
...
anticline
upward-arching folds
temperature,pressure,water can make?
magama
nuée ardente is
glowing cloud
ocean ridge
underwater ocean mountain chain
sliding boundries
two plates past each other
continental crust
The thickest type of crust.
low concentration of silica gives low
viscosity
plate tectonics
Earth's lithosphere are in constant motion
subduction
process where the ocean floor sinks beneath a deep-ocean trench
astherosphere
plastic-like layer of Earth on which the lithospheric plates float and move around
nuee ardente
fast moving incandescent mass of gas-enveloped particles
slab-pull
a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and "pulls" the trailing lithosphere along
spreading boundries
2 plates moving away from each other
tectonic plate
a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle
slab pull
the weight of a subducting plate (slab) pulls the rest of it into the subduction zone (trench)
fossil
a trace of an ancient organism that has been preserved in rock.
the longer the journy the more _____it becomes
felsic
75% percent of all volcanism that occurs above sea level happen around the margins of the
pacific ocean
subduction/subduction zone
Where two plates of different density converge, the denser one sinks into the mantle beneath the other/is a long, narrow belt where a lithospheric plate is sinking into the mantle.
asthenosphere
The solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it
Convection current
a current caused by the rising of heated fluid and sinking of cooled fluid
Transform Boundary
a plate boundary where two plates move past each other in opposite directions
Divergent boundry
A plate boundry where two plates move away from each other
magnetic symmetry
magnetic pattern on one side of an ocean ridge is the mirror image of the other side of the ridge
lithosphere
A rigid layer made up of the uppermost part of the mantle and crust
what are the four different types of convergent baundaries?
oceanic-oceanic, eceanic-continental,continetal-continental
hot spot
a concentration of heat in the mantle capable of producing magma, which rises to Earth's surface; The Pacific Plate moves over a hot spot, producing the Hawaiian Islands
Transform plate boundary
A plate boundary where two plates are sliding horizontally past each other.
strike slip fault
when forces cause rock to break and move horizontally
caused by shearing
san andreas fault
what are the three ways of making magma?
increasing temperature, decrease pressure, add water
Was Wegener's hypothesis widely accepted?
No! Since he could not describe the mechanism that moved the land, it was rejected
isochron line or isochron band of color
indicate the ocean floor is the same age
convergent
(volcano)
transform
strike/slip fault
What does Pangaea mean?
Entire earth
high gas pressures cause______
explosive eruptions
igneous rocks
paleomagnetism, as cool, preserve magnetic field and direction, lock in at curie point
hypothesis
a suggested explanation for an observation; often stated in the form of a question and answered by running an experiment to test the hypothesis
conservative plate baaundaries are also called
transform baundaries
mid-ocean ridges
places where sea-floor spreading takes place
Seismic Waves
virations that travel through earth carrying the energy released during an earthquake.
when the oceanic sbducts it creates?
volcanoe arc
Mt lassen bost the most recent
california eruption,
ocean drilling evidence
sediments from Glomar Challenger indicate that sediments are youngest closer to the mid-ocean ridge and older with increasing distance from the ridge
transform/slip boundary
A boundary where two plates rub together vertically or horizontally in opposite directions forming a fault. Earthquakes occur here..
tension
stress that occurs when forces act to stretch an object
The motion away from each other is also called______
rifting
iam a rack who is cooler, high viscosity, enrich in silica, light colored
felsic
Alfred Wegener
A German scientist who proposed the theroy of continental drift
divergent boundary
a plate boundary where two plates move away from each other
inner core
a dense sphere of solid iron and nickel at the center of the earth.
mid-oceanic ridge system
As they mapped the sea floor, oceanographers discovered the largest mountain chain on Earth
earthquake evidence
there is a close link between the location of deep focus earthquakes and ocean trenches (plate boundaries)
What theory has replaced Wegener's?
Plate tectonics! This theory proved Wegener was correct -- the continents did move!
what did scientist find by using echo signals along the ocean floor?
the mid atlantice ridge
decribe what is meant by plate
the oceanic crust and the land crust
what is the difference between oceanic lithosphere and continental lithosphere?
oceanic is denser and thinner, continental lithosphere is light weigth and thicker
Wavelength
...
Anapsida
No post-orbital openings
iceland
NA and Eurasion divergent
plates sliding past eashother
transform boundarys
stress
causes changes in the rock(shape, volume) and compresses or expands it
mountain range
formed at a continental-continental convergent boundary
Core
Center of the earth-metal and liquid
along earth's plates
where do earthquakes form?
Divergent
When 2 tectonic plates pull apart.
radiation
the transfer of energy through space
when plates push against each other
collision
20
About how many plates is the lithosphere broken into?
Granite
A usually light colored igneous rock that is found in continental crust
tectonic plates
individual sections of the lithosphere of the earth. They fit together in a way similar to a jigsaw puzzle, but are always moving very slowly, floating on the molten rock of the asthenosphere
Continental Drift
Hypothesis, created by Alfred Wegener, that states that the continents once formed a single landmass called Pangea, broke up, and drifted to their present locations
Spreading center-
Occurs at diverging oceanic plate boundaries (Mid-ocean ridges/ rift valleys) where rising lava sea floor spreads apart due to convection currents
...
What happens at the boudary when divergent plates move?
deep-ocean trench
deep underwater canyons where old crust returns to the mantle
faults
breaks in Earth's crust where rocks have slipped past each other
Continental Theory is also know as? (Large Land Mass)
Pangea
city with the highest population in the world
tokyo
basalt
A dark, dense, igneous rock with a fine texture, found in oceanic crust
Outer Core
liquid, super hot, mainly Iron and Sulfur
Harry Hess
an American geologist who studied the Mid-Ocean Ridge and proposed the theory of sea-floor spreading, which supported Wegener's theory of continental drift
Mantle Convection
heat from earths interior and outer cores is transferred through the mantle. according to mantle convection hypothesis, the mantle may be moving the plates along with it as it convects
Primary Wave
Wave which causes rock particles to move back and forth in the same direction the wave is traveling, the first wave to pass through after an earthquake
convection
the transfer of thermal energy in the mantle material that drives the plates
pressure
the force pushing on a surface or area
Oblique Fault
A fault in which diagonal movement occurs
isostatic adjustment
process establishing a new level of gravitational equilibrium
shield volcano
a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions
oxygen and silicon
most abundant elements in the crust
volcano
the opening in earth where the melted rock called magma is released
ancient climates
Land areas that show evidence of ancient glaciation are now located near the equator.
A subducted plate melts forming...
magma and volcanic mountains
epicenter
the point on the Earth's surface where the EQ began.
The hypothesis by Alfred Wegener of the plate tect
continental drift
Depth
This is how far under the earths crust the earthquake occurs.
magnetic stripes
Sections of the sea floor that appear in stripes of alternating magnetic directions.
convergent boundary
a plate boundary where two plates move toward each other
deep ocean trench
The trench created at a subduction zone in the ocean.
S-P interval
then your measure the first on in legth.
Continental Drift Theory
the theory that the continents have not always been in their present locations but have moved there over millions of years
Land mass called Pangaea
According to Wagener's hypothesis of continental drift, the continents were once joined together in a single....
the southern part of pangaea includes:
south America Africa Antarctia
Ridge Push
the rock that forms from the magma is very hot, at first it is less dense and more buoyant than the rocks farther away from the mid ocean ridge. however as the newly formed rock ages and cools it becomes denser. gravity causes this older denser lithosphere to slide away from the ridge down the slopping asthenosphere. as this happends, new rock is being made.
fault
a break in a body of rock along which one block slides relative to another; a form of brittle strain
What is Viscisity?
The ability of a substance to flow (higher viscosity=flows faster)
Surface wave
A type of seismic wave that forms when P waves and S waves reach Earth's surface., an energy wave from an earthquake that travels only at the surface and moves less quickly than P waves and S waves but makes the ground roll and sway, another way of saying "L wave"
convergent plate boundaries: subduction
the process by which one plate sinks beneath another. only oceanic plates subduct because only they are dense enough. the down buckling creates a deep trench, which can be 100 km wide and 10 km below sea level. if the overriding plate is a continental plate, a large mountain range can form parallel to the trench. it will have volcanoes from the melting material of the subducting plate.
Weakness of Continental Drift Theory
There was no real explanation why the continents moved/were moving
Explain the main difference between SIMA and SIAL in appearance and origin
oceanic crust - rich in silica and magnesium, thinner (under the water)
continental crust - above the water, thicker, rich in silica and aluminum, older, lighter rock
when the spoon touches a pot of hot soup
what is an example of conduction?
island arc
japan
San Andreas Fault
Transform Boundary
aesthenosphere
thin
molten rock
stuff the plates slide on
"peanut butter"
plate boundaries
divergent, convergent, and transform
temperature inside Earth
increases with depth
trench
long, steep-sided, narrow depression in the ocean floor
Pangea
large supercontinent that existed 250 million years ago
Divergent boundaries
Places where plates move apart
Volcanoes and trenches
Found along convergent (oceanic-oceanic, oceanic-continental) boundaries
Scientist known for Theory of Continental Drift
Wegener
rock crystals
form when rocks cool slowly
Tracking is measured in?
Centimeters per year
drawback
when the water quickly receeds from the beach in anticipation of a tsunami
Lithiosphere
consists of hard, strong, rigid rock. Contains all of the crust and the upper part of the mantle. 75-125 km thick. Floats on soft, plastic rock.
paleomagnetism
the study of the earth's magnetic field from rocks containing iron-bearing minerals
supercontinent cycle
The process by which supercontinents form and break apart over millions of years
Sonar
A device that determines the distance of an object under water by recording echoes of sound waves
glossopteris
a plant found on five diffrent continents, not possible for it to travle such distances.
ridges
are the youngest part of the seafloor
convection currents
Circular currents in the mantle caused by the magma being heated by the core off the Earth.
sea-floor spreading
the process by which new oceanic lithosphere (sea floor) forms as magma rises to Earth's surface and solidifies at a mid-ocean ridge
metal
Earths inner core is a dense ball of
lithospheric plate
section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust
normal polarity
the same magnetism as the present magnetic field
Mantle
The Layer of a planet in-between the Crust and Core, mostly made of molten material.
hanging wall
Rocks that break along angles create the foot wall and the hanging wall. The hanging wall is called the hanging wall because it is larger at the top than at the bottom, which allows a person to hang from the top of the wall.
Uplift
...is the rising of regions of the Earth's crust to higher elevations.
plate boundary
A place where the plates make up Earth's crust and upper mantle either move together or apart or move past each other.
rift valley
a deep valley that forms where two plates move apart
sea floor spreading
a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge;proposed by Harry Hess
Trough
a channel along the eaves or on the roof
early hypothesis before plate tectonics
earthquakes were created by underground air escaping explosively after being heated by central fires.
convergent boundry
a plate boundry where two plates move tward each other
extrusion
when igneous rock covers the top of a body of older rock
Rock on the ocean floor provideed the final proof
Magnetic reversal
s wave
a type of seismic wave that moves the ground up and down or side to side
Divergent plate boundary
A region where plates are moving apart and where new ocean or rift valley will eventually form. A spreading center forms the junction.
transformed plate boundaries
a plate boundary where two plates move past each other in opposite directions (can happen between: Oceanic—Oceanic crust, Continental—Continental crust, and Oceanic—Continental crust)
crust, lithosphere, asthenosphere, mantle, outer core, inner core
what is the correct order (starting from the surface) of Earth's layers?
Oceanic Fracture Zone
A crack or step in the elevation of the seafloor that forms as a transform fault along a mid ocean ridge but is no longer a plate boundary.
Convergent (ocean to continent) boundary
The two ocean crusts and continent crusts come together and the weaker one subducts.
Height of the Rocky Mountains
rise less than 5 KM above sea level
What continents made up each of the two smaller landmasses?
Laurasia- North America, Europe and Asia.
Gondwanaland- Africa, South America, India, Antartica and Australia.
NAME THE FOUR Layers of the Earth in order from inner to outer
Inner Core (hot, solid metals), Outer Core (liquid metals), Mantle(thickest layer,hot rock toward outer core and cool and rigid rock at very top), Crust(thin layer of cool rock). Density and heat INCREASE from outer to inner layers.
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