2. Earthquakes occur when

stress accumulates in the crust.
stress is released in the crust.
only when plates sink.
plates lock together.

3. Two common types of seismic waves generated by earthquakes are

"P" waves that arrive first and "S" waves that arrive secondarily.
"P" waves that are pressure waves and "S" waves that are swifter.
"P" waves that are shear waves and ''S" waves that are slower.
"S" waves that are shear waves and "P" waves that are slower.

4. The difference between the arrival of P and S waves

is a function of the intensity of the waves.
enables seismologists to calculate the strength of an earthquake.
is a function of the distance to the epicenter (source).
does not vary from earthquake to earthquake.

5. The location of the epicenter of an earthquake is found by

the collaboration of two seismic stations.
measuring the difference in arrival times for P and S waves by two seismic stations.
the collaboration of three or more seismic stations.
measuring the intensity of the P and S waves.

6. The Richter Magnitude Scale takes into account the

amount of ground motion and the distance to the epicenter.
amount of ground motion and the speed of the P waves.
height of the P, S and L waves and their speeds.
speeds of the P, S and L waves and their arrival times.

7. Theoretically the Richter Scale runs from -2 to infinity (according to the video), but the highest magnitudes possible seem to be about

7, because rock can only accommodate a limited amount of stress.
9, because rock can only accommodate a limited amount of stress.
9, because plates move too slowly to generate higher magnitudes.
9, because plates move intermittently allowing stress to be dissipated before they accumulate to greater levels.

8. A one unit jump on the earthquake magnitude scale (like 5 to 6) means about

10 times more energy is given off.
10 times less energy is given off.
30 times more energy is given off.
50 times more energy is given off.

9. Ground motions are caused primarily by the

rapid vibration of surface waves.
slower vibration and rolling motion of surface waves.
slower vibration of P and S waves.
rolling motion of P and S waves.

10. When the natural period of vibration for a building is

different from the period of the seismic waves, more damage is likely to occur.
different from the period of the seismic waves, more swaying occurs but less damage.
the same as the period of the seismic waves, less damage is likely to occur.
the same as the period of the seismic waves, more damage is likely to occur.

11. Which statement is not associated with the concept of amplification?

Seismic energy is added to a swaying building.
A building's natural period of vibration matches the period of the seismic wave.
The material under a building gives way and the building sinks into the ground.
Amplication is like pushing a child in a swing.

12. The area near Parksfield, California is being intensively studied for earthquake activity because

some of the biggest earthquakes in the U.S. have occurred there.
more earthquakes have occurred there than any other place in the U.S.
it is very accessible and near a center of seismic research.
moderate earthquakes have occurred there at about 22 year intervals since 1857.

13. Which of the following is not a goal of the Parkfield experiment.

Develop short term prediction methods for earthquakes.
Record the details of the earthquake generation process.
Determine the direction of motion along the San Andreas Fault.
The first hand study of a moderate earthquake.

14. The rock along a fault line can be studied by

direct seismic waves that give the density of the rock and reflected and refracted waves that reveal the layers.
direct seismic waves that show layering and reflected and refracted waves that give the density of the rock.
direct and reflected seismic waves that show layering and refracted waves that give the density of the rock.
direct and reflected seismic waves that give the density of the rock and refracted waves that show the layers.

15. Several techniques and monitoring devices are used along fault lines to detect motion and the build up of strain. Which of the following are not properly associated?

creep meters and alignment arrays - detect surface movement
creep meters and geodometers - detect surface movement
changes in ground water levels - indicate wide spread surface movement
geodometers - detect wide spread surface movement

Prepared by: Mike Mitchell

Be sure to review your quizzes before taking the test.