Lecture 14: Earthquakes

Flashcards to help understand key concepts related to earthquakes, including definitions of terms and phenomena related to seismic activity.

Earthquake

A sudden movement along a fault due to stress build up.

Fault

A fracture in rocks along which there has been movement.

Stress

The build up of energy along a fault before motion occurs.

Epicenter

The point on the Earth's surface directly above the focus of an earthquake.

Focus (Hypocenter)

The point within the Earth where an earthquake originates.

Magnitude

A measure of the energy released by an earthquake as represented on a scale from 1 to 10.

Seismic waves

Energy released during an earthquake that propagates away from the quake.

Liquefaction

A phenomenon where saturated soil loses strength and stiffness in response to an applied stress.

Seismometer

An instrument that measures the arrival of seismic waves.

Body Waves

Seismic waves that travel through the Earth's interior, including P waves and S waves.

Surface Waves

Seismic waves that travel along the Earth's surface and cause the most damage.

P waves

Primary waves that are compressional and can travel through solids, liquids, and gases.

S waves

Secondary waves that can only travel through solids and are blocked by liquid.

Triangulation

A method used to locate an earthquake's epicenter by using the arrival times of seismic waves at three different seismic stations.

Seismogram

A representation of the arrival time and intensity of seismic waves.

Seismic Energy

Energy released during an earthquake that propagates through various types of seismic waves.

Fault scarp

The exposed surface created by the movement along a fault.

Hazard Map

A map representing the intensity of earthquake damage or shaking.

Wave Refraction

The bending of seismic waves as they pass through materials of different densities.

Shadow zone

A region on the opposite side of the Earth from an earthquake's focus that does not experience seismic waves.