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The seismic scales

Richter scale

To assess the power of earthquakes, seismologist Richter introduced the notion of magnitude. It corresponds to the energy liberated in the focus of the seism and depends to the length of the active fault and the importance of the displacement.

Richter scale
Magnitude Earthquake effects
< 3.5 The earthquake is not felt, but recorded by seismographs
3.5 - 5.4 Often felt, but rarely causes damage
5.4 - 6 Slight damage to well-designed buildings, but can cause major damage to others
6.1 - 6.9 Can be destructive in areas up to about 100 km
7 - 7.9 Major earthquake. It can cause serious damage over larger areas
> 8 It is a very strong earthquake that can cause serious damage in areas several hundred kilometers across

MSK scale

Magnitude should not be confused with intensity which is assessed from the effects produced at the surface. To estimate it, the MSK scale must be used, which name comes from its fathers Medvedev, Sponheuer and Kamik in 1964.

MSK scale
Intensity Effects produced at the surface
Degree I Not felt
Degree II Slightly felt
Degree III Week quake partially felt
Degree IV Mostly felt
Degree V Wakening of sleeper
Degree VI Fright
Degree VII Damage to buildings
Degree VIII Destruction of buildings
Degree IX Damage is generalized to buildings
Degree X General destruction of buildings
Degree XI Disaster
Degree XII Landscape change

Examples of monitoring networks

Map of seimological stations in France

Though the seismic activity in France is not really high, seismologists monitor the ground movement. They have in this optic seismographs that enable the record of seismic waves.

Seimology laboratories are gathered mainly in the risky zones as shown opposite.

Seismograms obtained are analyzed and used after within numerous studies like those done at TAMARIS.