Earthquakes

A fault is ____.

• a place on Earth where earthquakes cannot occur

• a fracture in the Earth where movement has occurred

• the place on Earth’s surface where structures move during an earthquake

• another name for an earthquake

An earthquake’s epicenter is ____.

• the place on the surface directly above the focus

• a spot halfway between the focus and the surface

• the spot below the focus

• any spot along the nearest fault

When an earthquake occurs, energy radiates in all directions from its source, which is called the ____.

• epicenter

• focus

• fault

• seismic center

Earthquakes are usually associated with ____.

• violent weather

• faults

• large cities

• the east coast of North America

The hypothesis that explains the release of energy during an earthquake is called the ____.

• Richter hypothesis

• moment magnitude hypothesis

• vibration hypothesis

• elastic rebound hypothesis

The adjustments of materials that follow a major earthquake often generate smaller earthquakes called ____.

• foreshocks

• surface waves

• aftershocks

• body waves

Major earthquakes are sometimes preceded by smaller earthquakes called ____.

• Aftershocks

• Focus shocks

• Surface waves

• Foreshocks

Which seismic waves travel most rapidly?

• P waves

• S waves

• surface waves

• Tsunamis

What is the minimum number of seismic stations that is needed to determine the location of an earthquake’s epicenter?

• two

• one

• four

• Three

According to Figure 8-1, what is the distance between the seismic station and an earthquake epicenter, if the first S wave arrives 4.0 minutes after the first P wave?

• 1500 kilometers

• 2500 kilometers

• 3000 kilometers

• 2000 kilometers