CH 25 Flashcards
a system of mountain ranges on the sea floor separated by valleys
Mid-ocean ridge
a long narrow depression
rift valley
the boundary where two plates collide
convergent plate boundary
when the thick and buoyant continental plate meets a thin and dense oceanic plate the denser plate dives beneath the continent in the process is called
subduction
the boundary between two plates that are moving apart
divergent plate boundary
this type of boundary where plates slide horizontally past each other in opposite direction
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 moves
faults
this 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
who came up with the continental drift hypothesis
Alfredo Wegener
what are some evidence for the continental drift hypothesis?
- the continents matched up like puzzle pieces
- mountain ranges had the same rock type
- fossils of big animals were found
what was the super-continent called
Pangaea
who came up with the seafloor spreading hypothesis
Harry Hess
how did Harry Hess discover seafloor spreading
he used sonar
who discovered the MOR
Harry Hess
where is younger rock formed in the MOR
closer to the MOR
what are the 3 plate boundaries
divergent plate boundary
convergent plate boundary
transform plate boundary
how do convergent plate boundaries move
they collide together
subduction only happens with which type of plate boundary
convergent
what types of crust do we have
continental crust
oceanic crust
what type of crust has to be present for volcanic activity
oceanic crust
if two continental plates collide what will occur
a mountain will form
if oceanic and continental crust converge what will form
a deep sea trench or volcanoes
what can be created when two oceanic plates come together
an volcanic island and deep sea trench
what do hot spots create
volcanic islands
how do divergent boundaries move
they move away from each other
what are examples of a divergent plate boundaries
MOR(only oceanic crust) and East African Rift(only continental crust)
how do transform plate boundaries move
they move past each other
what is an example of a transform plate boundaries
San Andreas Fault
what types of crust are involved with transform plate boundaries
only continental
what is a convection current
- Magma heats up, become less dense,and rises
2. Magma cools, becomes more dense, and sinks
what is a fault
a crack in earth’s surface
which plate boundaries have shallow earthquakes
divergent and transform plate boundaries
which plate boundary has deeper earthquakes
convergent plate boundary
what are the four types of stress applied to rock
compression, tension, shear, and torsion stress
what are the two types of deformation
elastic and plastic deformation
what happens during plastic deformation
when the stress is removed it returns to it original shape
what happens to during plastic deformation
when stress is removed it remains in that new shape
what are the two types of body waves
primary waves, and secondary waves
how many seismic waves are there
three types: Primary, Secondary, Surface waves
what type of wave is a primary wave
a compression wave
which body wave moves the fastest
primary waves
what type of materials do P-waves travel through
solids and liquids
what type of wave is a secondary wave
transverse
what type of materials do S-waves travel through
only solids
what type of wave does the most damage
surface waves
what are the two scales to measure scales
Richter scale, Mercalli scale
what does the Richter scale measure
the amount of energy released
what does the Mercalli scale measure
the amount of damage
is the measure of a fluids resistance to flow
viscosity
is the chemical compound silicon dioxide,SiO2, which is a common ingredient in most magma
silica
tend to be small, have heights in the hundreds of meters range , and have short eruption cycles
cinder cone volcanoes
are broad, flat structures composed of layer upon layer of lava flows
shield volcanoes
are large and steep sided, often thousands of meters high and tens of kilometers across the base and composed if layers of both lava lava and ash
composite volcanoes
what is molten, or liquid, rocks stored inside earth called
magma
where is the ring of fire located
the Pacific Ocean
what forms when tectonic plates collide along a subduction zones
volcanoes
which two specific locations can volcanic activity occur due to divergences
Mid Atlantic Ridge and East African RIft Valley
are hot spots stationary
yes, they are in a set location
what are created from hot spots
volcanic islands (Hawaii)
if a liquid has a higher viscosity is it going to run faster or slower
slower
do magma that have higher viscosity does it have more or less silica
more the higher the viscosity the more silica and less silica the less viscosity
what is pyroclastic material
the solid material from a volcano
what is the smallest ptroclastic material
ash
what are the largest types of pyroclastic material
blocks and bombs
what are the types of gasses that come from a volcano
water vapor, carbon dioxide, sulfur dioxide
how are volcanoes classified
size, shape,and the materials that erupt
what are the 3 types of volcanoes
shield, composite and cinder cone
