Measuring Earthquakes

What are seismic waves?

• Energy released by an earthquake in waves or vibrations
• The point beneath Earth’s surface at which rock under stress breaks and triggers an earthquake
• The point on the surface directly above the point at which an earthquake occurs
• The strength of an earthquake

In what order do the three types of seismic waves arrive at a seismograph?

• S wave, P wave, Surface wave
• Surface wave, P wave and S wave
• P wave, S wave and Surface wave
• P wave, Surface wave and S wave

Which type of seismic wave produces the most severe ground movement?

• P wave
• S wave
• Surface wave
• None of the above

Describe the moment magnitude scale, and explain why it is useful in measuring earthquakes.

• It measures nearby earthquakes.
• It measures earthquakes total energy of earthquakes near or far
• It tells us how dangerous an earthquake was
• It measures the size of the largest wave.

How do geologists locate the epicenter of an earthquake?

• They measure the difference between seismic waves on three or more seismographs. The epicenter is where the circles intercept.
• They measure the difference between seismic waves on the first seismograph to receive the wave.
• They measure the largest surface wave to hit the surface.
• They add the total damage of the p wave, s wave and surface wave.

_____________ records ground movements caused by seismic waves as they
move through Earth

• Focus
• Epicenter
• Surface Waves 
• Seismograph

________ are the slowest seismic waves.

• P waves
• S waves
• Surface waves
• Epicenter

___________ is the point beneath Earth’s surface at which rock under stress breaks and triggers an earthquake.

• Focus
• Epicenter
• Surface waves
• Seismograph

 __________ is the point on the surface directly above the point at which an earthquake occurs.

• Focus
• Epicenter
• Surface waves
• Seismograph

True or False? The shaking and trembling that results from movement of rock beneath Earth’s surface is called an earthquake.

• True
• False, magma