Earthquakes, faults, waves

These documents provide a simplified and educational support designed to shed light on certain aspects for people who have questions about earthquakes. Particular attention is paid to the Rhône-Alpes region. They are intended for people who need to handle notions of seismology, engineering seismology and seismic engineering, without however.

When an earthquake occurs, seismic waves that propagate from the focus to the surface pass through different media. Depending on the nature of these geological layers, the impact of the earthquake will not be the same, as their mechanical characteristics are different. This is referred to as Site Effect to refer to this change in seismic tremor according to local geology.

Analyzing the vulnerability of buildings consists in trying to predict the behaviour of these constructions in the event of an earthquake, by integrating all our uncertainties.

It is not earthquakes that kill but buildings that collapse. We can protect ourselves from earthquakes by making homes resistant: this is the objective of seismic regulation.

For more than twenty years, the Sismalp network has been monitoring seismicity in southeastern France, from Lake Geneva to southern Corsica and from the Massif Central to northern Italy. An average of two earthquakes are detected and located each day by the forty or so seismological stations managed by Sismalp; however, the number of earthquakes felt by the population each year does not exceed thirty.

Several active ground movements around Grenoble are located near active faults.

To protect against the effects associated with earthquakes, we can consider four main components: forecasting, early warning, warning and prevention.

Michel Campillo, ISTerre researcher, signs an article in the magazine Pour la science N°409 November 2011.

Article (in french) published in "Images de la Physique" 2010 (CNRS) : De la banquise à la crûte terrestre : les lois d’échelle de la fracturation. Jérôme Weiss (LGGE) and David Marsan (ISTerre).