Evidence of Plate Motions
What are zipper-like chains of undersea mountains?
mid-ocean ridges
What type of current drives plate motion?
convection currents
There are three types of faults, normal, strike-slip, and what?
reverse
What type of volcano is tall and shaped like a cone?
cinder cone
What is a process where magma flows through a crack in Earth's crust and hardens into solid strips of new rock on both sides of that crack?
sea-floor spreading
What is it called when an oceanic plate moves below a continental plate?
subduction
What does the theory of plate tectonics say?
That Earth's crust is made of plates that are always moving
Compression results in which type of fault?
Reverse
What type of volcano is made from slow and steady quiet eruptions?
shield volcano
What is a plate boundary where two plates move past each other in opposite direction?
transform boundary
Further
Earth's plates move as fast as what?
fingernails grow
What type of waves occur in an earthquake?
S waves, P waves, and surface waves
What are the two types of eruptions?
Quiet and explosive
What is stress that stretches rock so that it becomes thinner in the middle?
Tension
Where were glossopteris fossils found that supported the idea of continental drift?
It was found in africa and south america
What are the three types of plate boundaries?
convergent, divergent, and transform
What instrument measures seismic waves produced by earthquakes?
Seismographs or seismometers
What causes different eruption types?
Gas content
What is a force that acts on rock to change its shape or volume?
Stress
What evidence from land features did geologists look at to support the theory of continental drift?
Mountain ranges on coasts that lined up
The sinking of oceanic crust below continental crust creates what feature?
ocean trenches
What are the two ways tsunamis can occur?
ocean floor uplift and landslides
How does a tiltmeter help volcanologists determine if a volcano is going to erupt?
They measure small changes in the ground
What is stress that pushes masses of rock in opposite directions, in a sideways movement?
Shearing