chapter 25 Flashcards
system of mountain ranges on the sea floor separated by valleys
mid ocean ridge
s long and narrow depression, formed in between peaks along the mid ocean ridge
rift valley
boundary where two plates collide
convergent plate boundary
denser plate goes under the lighter plate
subduction
boundary of two plates moving away
divergent plate boundary
boundary where plates slide horizontally past each other
transform plate boundary
sudden movement or vibration of the ground
earthquake
a crack in the earths crust along which a rock has moved
fault
sudden release of strain energy as rock moves across a fault
elastic rebound
the point of origin of an earthquake
focus
the point on earths surface right above the focus
the epicenter
who came up with the continental drift hypothesis
Alphrad Wegener
what was Wegener’s evidence for continental drift?
- fossils from separate continents matching 2. coast lines match 3. same rock types and ages
what was the name of the super continent?
Pangaea
who came with seafloor spreading hypothesis?
Harry Hess
how did Harry discover seafloor spreading?
Sonar
what did Harry’s sonar discover?
Mid Ocean Range
What are the different type’s of plate boundaries
- divergent plate boundary 2. transform plate boundary 3. convergent plate boundary
how do convergent boundaries move?
they converge
where do subduction zone happen?
convergent boundary
what two types of crust are used between plate boundaries?
oceanic crust and continental crust
what land forms are created from oceanic and continental crust form?
mountains and volcanoes and deep sea trench
what can form when two oceanic crust collide?
hot spots and deep sea trench
what type of land forms when two continental crust collide
mountains
How do divergent plate boundary’s move?
Apart from each other
Examples of divergent plate boundary’s
- mid ocean ridge(oceanic crust) 2. east African rift (2 continental crust)
How do transform plate boundary’s move?
They slide by each other
what is an example of a transform plate?
San Andres fault (continental crust)
what is a convection current?
- magma heats up, becomes less dense, and rises 2. magma cools, becomes more dense, and sinks
what are thre forces to contribute to plate motion
- slab pull 2. ridge push 3. friction
which plat boundary’s have shallow earthquakes?
divergent and transform plate boundary’s
which plate boundary has deep earthquake
convergent plate boundary
what are the types of stress that act upon rocks to cause stress?
- compression stress 2. tension stress 3. shear stress 4. torsion stress
what are the 2 types of deformation?
elastic deformation and plastic deformation
what happens to the rock when elastic deformation occurs
the rock snaps back to original shape
what happens to the rock when plastic deformation occurs
after its stretched, it stays in its new form
how many types of seismic waves are there?
- P-wave 2. S-wave 3. Surface wave
what type of seismic wave is the fastest
P-wave
what type of wave is a P-wave
compression wave
what type of materials can p-waves move through
solids and liquids
what type of wave is a S-wave
Transverse
what type of material can S-waves move through?
solids only
what waves deal more damage
surface waves
what scales help measure erathquakes
Richter scale and mercalli
what does a Richter scale measure
energy
what does a Mercalli scale measure
damage done
