Rouans: geology and natural hazards

Seismic zone

3 of 5 (moderate)

Radon potential

Category 3 of 3 (significant potential)

Recognised natural disasters

9 since 1988

Underground cavities recorded

None

Ground movements recorded

2

Risk prevention plans

None

Natural and technological hazards to which the commune is exposed, according to the national GASPAR database.

• Inondation: par une crue à débordement lent de cours d’eau, par ruissellement et coulée de boue
• Mouvement de terrain: tassements différentiels
• Séisme
• Phénomène lié à l’atmosphère: tempête et grains (vent), foudre, grêle, neige et pluies verglaçantes
• Radon
• Transport de marchandises dangereuses

9 events recognised as a natural disaster by ministerial order since 1988.

• Inondations et/ou coulées de boue: 8
• Mouvement de terrain: 1
• Sécheresse: 1

1. Inondations et/ou coulées de boue

   Event from 16/06/2024 to 20/06/2024, order published in the Journal officiel on 27/09/2024.

2. Inondations et/ou coulées de boue

   Event on 01/03/2020, order published in the Journal officiel on 10/07/2020.

3. Inondations et/ou coulées de boue

   Event from 01/07/2018 to 02/07/2018, order published in the Journal officiel on 03/11/2018.

4. Inondations et/ou coulées de boue

   Event on 11/06/2018, order published in the Journal officiel on 15/08/2018.

5. Inondations et/ou coulées de boue

   Event on 01/07/2009, order published in the Journal officiel on 14/11/2009.

6. Sécheresse

   Event from 01/07/2005 to 30/09/2005, order published in the Journal officiel on 05/07/2008.

7. Mouvement de terrain, Inondations et/ou coulées de boue

   Event from 25/12/1999 to 29/12/1999, order published in the Journal officiel on 30/12/1999.

8. Inondations et/ou coulées de boue

   Event from 17/01/1995 to 05/02/1995, order published in the Journal officiel on 24/02/1995.

9. Inondations et/ou coulées de boue

   Event from 01/02/1988 to 29/02/1988, order published in the Journal officiel on 21/04/1988.

Seismic zone

Zone 3 of 5: moderate. This regulatory zoning, in force since 2011, sets the rules for earthquake-resistant construction.

Radon potential

Category 3 of 3: significant potential. At least part of the commune has higher-than-average uranium content. Radon is a naturally occurring radioactive gas that can build up in poorly ventilated rooms.

What BRGM maps say at the town hall. They describe that single point: elsewhere in the commune, the ground may be quite different.

• Shrink-swell clays

• Rising groundwater

• Underground cavities

• Ground movements

• Earthquakes

• Nature of the ground

Recorded across the whole commune by BRGM, in its national databases of underground cavities and ground movements.

No underground cavity recorded (quarries, cellars, military works, natural cavities…).

2 ground movements recorded (landslides, rockfalls, collapses, mudflows…).

See cavities and ground movements on the map

No risk prevention plan is listed for the commune.

• Vue (44)
• Cheix-en-Retz (44)
• Le Pellerin (44)
• Frossay (44)
• Saint-Hilaire-de-Chaléons (44)
• Sainte-Pazanne (44)
• Chaumes-en-Retz (44)
• Port-Saint-Père (44)

Listed hazards, natural disasters, seismic zoning, radon potential, cavities, ground movements and prevention plans: Géorisques, published by the French ministry for the ecological transition, under Licence Ouverte Etalab 2.0, data accessed on 02/11/2026. Summary beneath the town hall: BRGM map services, queried when the page is displayed. List of communes and populations: API Découpage administratif (geo.api.gouv.fr), d’après le code officiel géographique de l’Insee, version of 30/10/2026.

This information reflects the state of knowledge at the scale of the commune or of a single point. It replaces neither a soil survey nor the official risk statement (état des risques) required for a sale or a rental, which is drawn up on the official French government service.