Ch.8 & 9 Review

What causes an earthquake?
Earthquakes are caused by the vibrations of Earth’s produced by the sudden release of energy
Describe the location of an epicenter and focus.
Epicenter is the location on the surface of Earth directly above the focus. Focus is the point within the Earth where the earthquake starts.
What is the elastic Rebound Hypothesis? How does it relate to earthquake?
Elastic rebound hypothesis is the release of built-up energy. Most earthquake are produced by the release of elastic energy stored in rocks that has been subjected to great forces
Describe aftershocks and fore shocks.
Aftershocks are small quakes that come after a major earthquake. Fore shocks are small quakes that come before a major earthquake.
How are earthquake measured?
Historically, scientist have used two different types of measurement to describe the size of an earthquake-intensity and magnitude
Describe the following earthquake waves: surface, S waves, and P waves.
Surface waves= seismic waves that travel along Earth’s outer layers. They move up, down, and side to side. Most destructive earthquake wave. Last to arrive at the seismograph.
S waves= shake particles at right angles to their travel.
P waves= They push and pull rocks in the direction the wave travels.
How do scientist locate earthquakes?
The difference in velocities of P waves provides a way to locate the epicenter.
Where do most earthquake occur?
Most of these occur around the outer edge of the Pacific Ocean.
Describe each of the different scales used to measure earthquakes.
Richter Scale= measures the magnitude of an earthquake.
What is liquefaction?
Stable soil turns into a liquid that is not able to support buildings or other structures
What causes tsunamis? What warning system is used?
A tsunamis is called a seismic sea wave. A tsunami is triggered by an earthquake. It occurs where a slab of ocean floor is displaced vertically along a fault.
What are some other dangers that can occur due to earthquakes?
Landslides and ground subsidence or the ground triggered by the vibrations occurs.
Describe the layers of the crust:
Crust-lithosphere
The lithosphere consists of the uppermost mantle.
It is cool and rigid shell
100 kilometers thick
Describe Continental Drift:
The continental drift hypothesis stated that the continents had one been joined to form a single supercontinent.
Who came up with the idea of continental drift?
Alfred Wegner
What is Pangaea?
Supercontinent
When did Pangaea form?
500MY
What kind of evidence is present to verify the idea of continental drift?
Shorelines look they fit together
What is plate tectonics?
According to the plate tectonics theory, the uppermost mantle, along with the overlying crust.
How many plates are there?
There are 7 major plates and 6 minor plates. The largest is the Pacific plate which covers most of the Pacific ocean.
What happen at plate boundaries
The grinding movement of Earth’s lithosphere plates generate earthquakes, create volcanoes, and deform large masses of rock into mountains.
Describe each of the boundaries and tell what is happening at each
Divergent and Convergent, Transform
What are some evidences of plate tectonics?
Paleomagnetism, Earthquake patterns, Ocean drilling, Hot spots
What is the driving force of plate tectonics?
Convection occuring in the mantle is the basic driving force for plate movement.
What are hot spots
A concentration of heat in the mantle capable of producing magma, which rises to Earth’s surface