Earthquakes & Natural Hazards

A series of flashcards covering key vocabulary related to earthquakes and natural hazards, including definitions and explanations of important concepts and types.

Earthquake

Vibration of Earth produced by rapid release of elastic energy caused by deformation.

Deformation

Changes in form and/or size of rock body, including displacement, rotation, and distortion.

Brittle deformation

A type of deformation where atomic bonds break and result in permanent cracks.

Ductile deformation

A type of deformation where bonds break but new bonds form quickly, allowing shape change without permanent cracks.

Fault

Major deformation that causes earthquakes in the brittle part of the lithosphere.

Stress

Force applied to a given area, which causes rock deformation.

Epicenter

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

Hypocenter

The focus of an earthquake located below the surface.

Aftershocks

Smaller earthquakes that occur as adjustments after a major earthquake.

Seismometer

An instrument that records the arrival of seismic waves during an earthquake.

Mercalli Intensity Scale

A scale that measures the severity of an earthquake based on its perceived shaking and damage.

Richter Magnitude Scale

A scale that measures the magnitude of an earthquake based on the amplitude of the largest seismic wave recorded.

Fault creep

A slow, gradual displacement along a fault.

Displacement

Movement along a fault that occurs during an earthquake.

P-waves

Primary waves that have a push-pull motion and can travel through solids, liquids, and gases.

S-waves

Secondary waves that have a shake motion at right angles and can only travel through solids.

Surface waves

Waves that travel along the outer part of the Earth and cause the greatest destruction.