Rossi–Forel scale
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
- Richter magnitude scale
- Seismic intensity scales
- Seismic magnitude scales
Bibliography
- Tiedemann, Herbert (1992). Earthquakes and Volcanic Eruptions. A Handbook on Risk Assessment. Zurich: Swiss Reinsurance Company.