Desk CH 25 Flashcards
system of mountain ranges on the seafloor separated by valleys
mid-ocean range
a long, narrow depression formed in between peaks along the mid-ocean range
rift valley
the boundary where two plates collide
convergent plate boundary
when a thick and buoyant continental plate meets a thin and dense oceanic plate, “the denser plate dives beneath the continent
subduction
the boundary between two plates that are moving apart
divergent plate boundary
plates slide horizontally past each other in opposite directions
transform plate boundary
is the sudden movement or vibration of the ground that occurs when rocks slip and slide along enormous cracks in Earth’s crust called faults
earthquake
is a crack in Earth’s crust along which rock has moved
fault
sudden release of strain energy as rock moves along a fault
elastic rebound
the point of origin for an earthquake
focus
the point on Earth’s surface directly above the focus
epicenter
what were pieces of evidence that supported his hypothesis
large animal fossils, coastlines matched up like puzzle pieces, mountain ranges matched up(also had same rock composition)
what was the name of the super continent?
Pangaea
Who came up with the continental drift hypothesis?
Alfred Wegener
who came up with the Sea Floor spreading hypothesis?
harry hess
What did Hess use to help him create a map of the sea floor?
sonar
where will younger rock be found on the sea floor?
closer to the MOR or near the MOR
who discovered the mid-ocean ridge
harry hess
what are the three types of plate boundaries?
divergent boundary,convergent boundary, and transform boundary
close together or collide
convergent
subduction only happens with which type of plate boundaries
convergent
what are the two types of crust are involved in plate
oceanic crust
continental crust
what lands form when oceanic crust and continental convert
oceanic trenches
what land forms can be formed when two oceanic crust collide
hot spots= they create islands
what land is created when two continental collide?
mountains
What type of crust must be presented from volcanoes activity occur?
ocean crust
how do divergent plate boundaries move
they come apart
what are 2 examples of divergent plate boundary’s
an MOR(Mid- Ocean Ridge, made up of oceanic crust) . The East African Rift( made up of continental)
how do transform boundaries move?
slide by each other
what is a specific example of a transform boundary
San Andres Fault
what continental crust or involved with transform plate boundary
what is a convenient current
- magma heats up, becomes less dense, then it rises 2. magma cools down, more dense, then goes down/ sinks
what are the other forces that helps plate movement
slab pull, ridge push, friction
What two types of boundaries have shallow earthquakes?
divergent and transform boundaries
which type of plate boundary has deep earthquakes?
convergent plate boundaries
what are the type of stresses that can be applied to rocks?
compression, tension, shear, and torsion stress
what are the two types of deformation?
elastic and plastic deformation
what happens to a rock whenever elastic deformation happens
deforms then it returns to it’s original shape
what happens to a rock whenever plastic deformation happens
it deforms and stays in that new shape
what are the Seismic Waves
primary,secondary, and surface
what type of seismic waves move the fastest
primary
how do primary waves move?
they are compression waves
what type of materials do they move through
solids and liquids
how do secondary waves move
transverse waves
what type of material do secondary waves move through
solids
which type of wave is most complex and causes the most damage
surface waves
what are the scales used to measure earthquakes
richter and mercalli scale
what does a richter scale tell us about an earthquake
the amount of energy released
what does the mercalli scale tell us about an earthquake
the amount of damage done
