Physical Geography: Natural Hazards (Tsunami and Tropical Cyclones)

This set of vocabulary flashcards covers the definitions, characteristics, and formation mechanisms of tsunamis and tropical cyclones as discussed in the physical geography lecture notes.

Natural hazards

A natural event that has the potential to affect people, place and infrastructure, categorized as geological, meteorological, or biological.

Tsunami

A Japanese word meaning "harbour wave" that refers to a series of fast-moving, long period waves generated by large disturbances below or near the seafloor.

Wave Period

The time taken for a wave to get from point A to B; for tsunamis, this is typically $15-60$ minutes, compared to $6-12$ seconds for typical wind waves.

Tsunami Velocity (Deep Water)

The speed at which tsunamis travel in the deep ocean, often exceeding $500\,km/h$ and reaching up to $800\,km/h$ (comparable to a 747 jumbo jet).

Submarine Earthquakes

The cause of most tsunamis, occurring when a subduction-zone earthquake snaps the leading edge of the continent up and forward, displacing a huge volume of water.

Deep-ocean Assessment and Report of Tsunami (DART)

A warning system network using buoys and bottom pressure recorders to detect seismological changes and provide warnings of tsunami waves.

The 2004 Boxing Day Tsunami

A catastrophic event triggered by a Magnitude $9.3$ earthquake off the coast of Sumatra, resulting in the deaths of approximately $280,000$ people.

Tropical Cyclone

An intense circular storm characterized by low pressure, high winds, and heavy rain, involving a mass of air rotating clockwise in the southern hemisphere.

Coriolis Force

A force caused by the Earth’s rotation that deflects air or water in motion, which would otherwise travel in a straight line.

Latent Heat

Energy released during condensation that provides a tropical cyclone with more power and results in higher cumulonimbus clouds.

The Eye

The center of a tropical cyclone, usually $30-50\,km$ across, characterized by clear skies, warm weather, light winds, and no rain.

The Eyewall

The region of a tropical cyclone with the maximum wind speed, heaviest rain, and often lightning.

Rainbands

Bands of cumulonimbus clouds that exist at the edge of a tropical cyclone and spiral around the core, producing heavy rain.

Wind Shear

Light (not strong) winds at high levels required for the formation and maintenance of a tropical cyclone.

Saffir-Simpson Hurricane Wind Scale

A $1$ to $5$ rating based on a hurricane's sustained wind speed used to estimate potential damage.

Storm Surge

An impact of tropical cyclones caused by wind set up and pressure set up, which can result in significant flooding in coastal areas.

Landfall

The point when a tropical cyclone reaches land, causing it to lose energy because it is no longer drawing power from the warm sea surface.