Plate Tectonics Flashcards
What was the name of the scientist who introduced Continental Drift
Alfred Wegener
What does the continental drift hypothesis suggest
that the continents have moved/drifted from one location to another
what did the continents do that supported continental drift
they fit together like a puzzle
What did rock formations have to do with continental drift
they match up along south america and africa
what do fossils have to do with continental drift
fossils of the same species (mesosaurus) were found in south america and africa
what evidence for continental drift is on rocks
climate change
what kind of fossil is found on Antarctica, india, and south america that supports continental drift
a type of fern fossil (glossopteris)
what is the theory of pangaea
about 225 million years ago, all the continents were connected to form a supercontinient called pangaea
what is the theory of plate tectonics
peices of earths lithosphere are in constant, slow motion, driven by convection currents in the mantle
what does the theory of plate tectonics explain
the formation, movement, and subduction of earths plates
what are plate boundaries
the interference/area between the crustal plates where earthquakes and volcanoes are most common
whats a fault
a break in the lithosphere along which movement has occurred
what are the types of plate boundaries (names)
divergent, convergent, transform
what motion do divergent plate boundaries make
two tectonic plates that move away from eachother
what motion do convergent plate boundaries make
two tectonic plates that move torwards eachother
what motion do transform plate boundaries make
two tectonic plates that slide past one another in oppposite directions
what type of plate boundary is a subduction zone
convergent
how do subduction zones work
the ocean floor sinks beneath a deep ocean trench and back into the mantle
what does a subduction zone allow the ocean floor to do
allows it to sink into the mantle and melt into molten rock
who are geologists
scientists that study the forces that make and shape the planet earth
what do geologists study about rocks
their chemical and physical characteristics
what do geologists search for clues about
earths history
what do constructive forces do to earth
shapes earths surface by building up mountains and landmasses
what do destructive forces do to earth
slowly wear away mountains and other features on the earths surface
what is the first layer of earth
crust
what is the second layer of earth
mantle
what is the third layer of earth
outer core
what is the fourth layer of earth
inner core
what natural cause is a seismic wave
earthquake waves
what do scientists do with seismic waves
stud the speed of these waves and the path they take
what model did seismic waves help put together
the layers of earth
what is convection
the transfer of energy/heat through a gas or liquid
what are convection cells
a circulating system of motion within a fluid or gas in which temperature and density differences exist
how does temperature affect convection cells
in the warmer, less dense portion of the cell, motion is upward; in cooler, denser portions, motion is downward
what is volcanism
any activity that includes the movement of magna onto or torwards the surface of earth
what is magma
molten rock;melted rock that is below the surface
what is lava
molten rock that errupts onto the earths surface
what is a volcano
a weak spot in the crust where molten material (magma) comes to the surface
what is a vent
the opening through which molten rock flows onto the surface
the ring of fire is a volcanic ____
belt
what is the ring of fire formed by
many volcanoes that rim the pacific ocean
what 3 places do volcanoes form
subduction zones, hot spots, and mid-ocean ridges
what is a hot spot
magma works its way up to the earths surface like a blow torch
what can hot spots create
volcanic islands or island arcs
how are hawaiian islands formed
island arcs
what is an island arcs
string of islands formed by a volcano
What is the focus of an earthquake
the point beneath earths surface where rock is under stress breaks (earthquakes)
what is the epicenter of an earthquake
the point on the surface directly above the focus
what is magnitude
a measure of the energy relaeased by an earthquake and ground motion
what does the mercalli scale measure by
the intesity of an earthqake by the amount of damage it caused
what does the mercalli scale use as numbers
roman numerals (I-XII) (1-12)
What does the moment magnitude scale record
the magnitude of an earthquake and its strength
what does the moment magnitude scale use as numbers
regular numbers 1-10
what are body waves
waves that travel from the focus aof an earthquake through the interior of earth
what are the 2 types of body waves
P-waves and S-waves
what are P-waves also known as
primary waves or compression waves
what motion do P-waves make
squeeze and stretch rock moterials as they pass trough earth
what can P-waves travel through
any material including solids, liquids, and gases
what are S-waves also known as
secondary waves or shear waves
what motion do S-waves make
particles vibrate at right anglesto the direction of travel of the wave (side to side like a snake)
what can S-waves travel trhough
solids, but not liquid
which body wave is quicker
P-waves
what parts of earths interior can P-waves travel through
all of earths interior
what parts of earths interior can s-waves travel though
everything exept the outer core (its a liquid)
