An Attempt to Compare the Beaufort Scale (Arithmetic Progression) to the Richter Scale (Logarithmic Base10 Progression)




Beaufort Scale - Sir Francis Beaufort (1774-1857)


Seismic Disturbances - Richard Ames Hart (1946- )

Hurricane - As Experienced at Sea - Sea completely white with driving spray; visibility very seriously affected.


Meteor Impact - Makes a mess of the planet for centuries; hastens evolution.

Violent Storm - Exceptionally high waves (small and medium-size ships might be for a time lost to view behind the waves). Everywhere the edges of the wave crests are blown into froth.


Tsunami - Wipes out coastal villages. Survivors of the wave coming in are swept away, killed or injured by debris in torrent flowing out.

Storm - Very high waves with long over- hanging crests. The 'tumbling' of the sea becomes heavy and shock-like. Visibility affected.


Glacier Avalanche / Volcano - Creates icebergs / buries or destroys climbing expeditions.

Visible effects brought about by force of wind.


Richter Scale - Charles Francis Richter (1934)

Severe Gale - As Experienced on Land - At a Beaufort Number of 9 slight structural damage occurs (chimney-pots and slates removed).


Epic Earthquake - At a Richter Magnitude of 9 complete devastation and large-scale loss of life occurs. Raising any Richter Magnitude by 1 multiplies (a.) the measured amplitude of the quake by 10 and (b.) the energy released by the tectonic shift in the earth by 33.

Gale - Breaks twigs off trees; generally impedes progress.


Great Earthquake - Very few buildings stay up. Bridges fall down. Objects are tossed into the air. Some are swallowed up by the earth.

Near Gale - Whole trees in motion; inconvenience felt when walking against the wind.


It is hard to keep your balance. The ground cracks. Roads shake. Many buildings are badly damaged.

Strong Breeze - Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty.


Newsmaker - Pictures can fall off walls. Furniture moves. In some buildings, walls may crack.

Fresh Breeze - Small trees in leaf begin to sway; crested wavelets form on inland waters.


If you are in a car, it may rock. Glasses and dishes may rattle. Windows may break.

Moderate Breeze - Raises dust and loose paper; small branches are moved.


Trembler - Buildings shake a little. It feels like a truck is passing by your house.

Gentle Breeze - Leaves and small twigs in constant motion; wind extends light flag.


You may notice this quake if you are sitting still, or upstairs in a house. A hanging object, like a model airplane, may swing.

Light Breeze - Wind felt on face; leaves rustle; ordinary vanes moved by wind.


Microearthquake - Trees sway. Small ponds ripple. Doors swing slowly. Maybe it was a ghost.

Light Air - Direction of wind shown by smoke drift, but not by wind vanes.


Earthquakes this small happen below ground. You can't feel them.

Calm - Smoke rises vertically.


You're in outer space.


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