Ground movement risk
Landslides or shrink-swell of clay soils (linked to drought) have been observed in the commune of Montpellier.
What is a landslide?
A landslide is a more or less sudden movement of the ground or subsoil. It can be of natural origin (erosion, gravity, earthworks, etc.) or man-made (exploitation of materials, deforestation, earthworks, etc.).
This phenomenon includes various manifestations, slow or rapid, depending on the initiating mechanisms, the materials considered and their structure:
- Slow movements leading to progressive deformation of the land, not always perceptible to man. They include:
- subsidence,
- earthworks,
- slides,
- solifluction,
- creep,
- shrink-swell of clay soils,
- mowing
- Rapid movements spreading abruptly and suddenly. They include:
- collapses linked to the presence of underground cavities,
- rock and boulder falls,
- slumps and mudflows
Consequences: houses, buildings and networks (roads, electricity, water, etc.) may be threatened or even damaged (cracks, changes to the landscape, etc.)
.Adopt the right reflexes
Before
- Inform yourself of the risks involved and safeguard instructions
During
- Respect the authorities' instructions
Inside:
- At the first signs evacuate the building and do not return
- Do not take the elevator
Outside:
- Remove yourself from the danger zone
- Rejoin a regrouping area
- Don't phone, clear the lines for rescue
After
- Close off gas and electricity
- Assess damage and dangers
- Make an inventory of your damage and prepare your insurance files
The risk of landslides in Montpellier
On the communal territory, types of ground movement are observed locally or are likely to occur such as:
- Landslides
- Shrinkage and swelling of clay soils (linked to drought)
- Collapses of underground cavities
- The risk of clay shrinkage and swelling is mainly present in the northern part of the town, including the districts:
- Hôpitaux facultés
- Mosson
- Les Cévennes
Preventive and protective measures
Surveillance and protective measures
Earth movement phenomena are highly random. When they present a significant risk to the population, close surveillance measures (instruments,...) of the site and protective works (protective screens or anti-submarine netting, wall purging, drainage system...) are implemented aimed at limiting their effects.