Rossi-Forel scale
The Rossi-Forel scale is a historical scale for classifying earthquakes according to their intensity , published by Michele Stefano de Rossi and François-Alphonse Forel in 1881 and 1883 . After a few forerunners in the 16th to 18th centuries, it is the oldest of the usual intensity scales and is still used in Switzerland today. In contrast to most of the other scales still in use today with 12 degrees of strength, the Rossi-Forel scale has 10 intensity levels.
In contrast to magnitude scales , such as the well-known Richter scale , an intensity scale describes the effects of an earthquake on the landscape, streets or buildings that can be perceived without instruments ( macro-seismics ). Depending on the local conditions, a single earthquake classified according to such a scale can have different strengths in different places. Examples of other intensity scales are the JMA scale , the European macroseismic scale (EMS scale) or the Mercalli scale .
| Degree of strength | observation |
|---|---|
| I. | Only noticeable by a trained observer, can be registered with a seismograph . |
| II | Few people who are at rest feel the tremor. |
| III | Several people who are at rest feel the tremor. |
| IV | People who work or are otherwise employed feel the tremor. Windows, doors and hallways make noises, moving objects are shaken. |
| V | The quake is generally perceived. Larger objects are also shaken, individual, free-hanging, smaller bells (house bells) strike. |
| VI | Even sleepers wake up. Larger furnishings such as floor lamps sway, mechanical (pendulum) clocks stop. All smaller bells hanging freely (house bells) strike. Visible swaying of plants, especially trees and bushes. Individuals flee their homes in shock. |
| VII | General horror. Movable objects topple over, larger bells like church bells strike. Minor damage to the building (breaking out of wall or ceiling plaster), but generally no damage to the building structure. |
| VIII | Damage to buildings such as cracks in walls and falling chimneys |
| IX | Building damage or complete destruction of buildings |
| X | Disaster , change in the surface of the earth |
literature
- Götz Schneider: Earthquake. Origin - spread - effect. Ferdinand Enke Verlag, Stuttgart 1975. ISBN 3-432-87601-7