A tsunami is a series of sea waves, usually triggered by an earthquake, landslide or volcanic eruption displacing a large volume of water. A hurricane is a rotating tropical storm powered by warm ocean water. One is a geological event that happens to travel through the sea; the other is weather.
The core difference
Both arrive from the ocean and both flood coastlines, which is where the similarity ends.
- tsunami — sea waves from a sudden displacement of water: earthquake, landslide, volcanic eruption.
- hurricane — a rotating storm system fuelled by warm ocean water, bringing wind, rain and storm surge.
Why a tsunami is not a tidal wave
The old term tidal wave is misleading and has largely been dropped: tsunamis have nothing to do with tides. Tsunami is Japanese — tsu, harbour, and nami, wave — named for the fact that they are barely noticeable in deep water and rear up on reaching shallow coastal waters.
Warning time
This is the difference that matters most practically. Hurricanes are tracked for days in advance. A tsunami from a nearby earthquake may allow only minutes, which is why coastal warning systems focus on detecting the quake rather than the wave.
Frequently asked questions
Can a hurricane cause a tsunami?
No. Hurricanes cause storm surge, which is wind-driven water piling against the coast. A tsunami requires a sudden displacement of water, usually seismic.
Why is "tidal wave" the wrong term?
Because tsunamis have nothing to do with tides. They are caused by displacement of water, typically by an earthquake.
What does the word tsunami mean?
Harbour wave, from Japanese tsu and nami — named because the waves are barely visible in deep water and rise dramatically near shore.