Understanding Earthquakes and Seismic Activity

What is an earthquake?

• A sudden shaking of the ground caused by seismic waves.

• A type of wave generated by explosions.

• A fracture in the Earth's crust.

• A measure of the effects of an earthquake.

What are seismic waves?

• Vibrations generated by earthquakes or explosions.

• The point on the Earth's surface above the focus.

• Lower-magnitude earthquakes that follow the main shock.

• A theory explaining how stress builds up in rock.

What is a fault line?

• A fracture in the Earth's crust.

• The underground point where an earthquake originates.

• A series of waves caused by underwater seismic activity.

• An instrument that records ground motion.

What is the focus of an earthquake?

• The underground point where an earthquake originates.

• The point on the Earth's surface directly above the focus.

• A process where soil behaves like a liquid.

• A subjective scale measuring earthquake intensity.

What is the epicentre of an earthquake?

• The point on the Earth's surface directly above the focus.

• A series of waves caused by the displacement of water.

• An estimate of the energy released during an earthquake.

• An instrument that detects tsunamis.

What are aftershocks?

• Lower-magnitude earthquakes that follow the main shock.

• Minor tremors preceding a larger earthquake.

• The fastest seismic waves.

• Structures designed to withstand seismic forces.

What does the Elastic Rebound Theory explain?

• How stress builds up in rock masses until it exceeds their strength.

• The process of soil behaving like a liquid.

• The measurement of earthquake intensity.

• The detection of tsunamis in real time.

What are P-Waves?

• Primary seismic waves that are the fastest.

• Secondary seismic waves that move in a side-to-side motion.

• Waves caused by the displacement of water.

• An instrument that records ground motion.

What are S-Waves?

• Secondary seismic waves that move in a side-to-side shearing motion.

• Primary seismic waves that are compressional in nature.

• A subjective scale measuring earthquake intensity.

• A process where soil behaves like a liquid.

What is a tsunami?

• A series of waves caused by the displacement of a large volume of water.

• A measure of the effects of an earthquake.

• An instrument that detects tsunamis.

• A type of seismic wave.