Rossi–Forel scale

Source: Wikipedia, the free encyclopedia.

The Rossi–Forel scale was one of the first

Mercalli intensity scale
in 1902.

The Rossi–Forel scale and/or its modifications is still used in some countries, such as the

PHIVOLCS Earthquake Intensity Scale
.

Scale

The 1873 version of the Rossi–Forel scale had 10 intensity levels:

Scale level Ground conditions
I. Microseismic tremor Recorded by a single seismograph or by seismographs of the same model, but not by several seismographs of different kinds. The shock felt by an experienced observer.
II. Extremely feeble tremor Recorded by several seismographs of different kinds. Felt by a small number of persons at rest.
III. Feeble tremor Felt by several persons at rest. Strong enough for the direction or duration to be appreciable.
IV. Slight tremor Felt by persons in motion. Disturbance of movable objects, doors, windows, cracking of ceilings.
V. Moderate tremor Felt generally by everyone. Disturbance of furniture, ringing of some bells.
VI. Strong tremor General awakening of those asleep. General ringing of bells. Oscillation of chandeliers, stopping of clocks, visible agitation of trees and shrubs. Some startled persons leaving their dwellings.
VII. Very strong tremor Overthrow of movable objects, fall of plaster, ringing of church bells. General panic. Moderate to heavy damage buildings.
VIII. Damaging tremor Fall of chimneys. Cracks in the walls of buildings.
IX. Devastating tremor Partial or total destruction of buildings.
X. Extremely high intensity tremor Great disaster, ruins, disturbance of the strata, fissures in the ground, rock falls from mountains.


See also

Bibliography

  • Tiedemann, Herbert (1992). Earthquakes and Volcanic Eruptions. A Handbook on Risk Assessment. Zurich: Swiss Reinsurance Company.