Mayenne

Recorded Natural Hazards (Géorisques)

It has 240 municipalities and 305,468 inhabitants. Under the seismic zoning in force since 2011, its highest seismicity is low (zone 2 of 5). A natural disaster has been declared 959 times since 1982 (one declaration per municipality and decree), mostly for floods (697) and ground movements (252). The most recent was signed on 18 May 2025. 168 municipalities have a high radon potential (category 3), home to 76% of inhabitants. 16 municipalities are covered by an approved natural hazard prevention plan.

Seismicity Zones

Number of municipalities in each zone of the regulatory seismic zoning (from 1, very low, to 5, high).

Natural Disasters Declared Since 1982

Declarations per five-year period.

Most Widespread Events

• 1999Ground Movements · 25 December 1999240 municipalities
• 1999Floods and Mudflows · 25 December 1999240 municipalities
• 1995Floods and Mudflows · 17 January 199556 municipalities
• 2024Floods and Mudflows · 17 June 202434 municipalities
• 2018Floods and Mudflows · 9 June 201824 municipalities
• 2012Floods and Mudflows · 27 July 201224 municipalities

Most Frequently Affected Municipalities

• 22Laval
• 13Changé
• 13Saint-Berthevin
• 11Château-Gontier-sur-Mayenne
• 10Bonchamp-lès-Laval
• 9Chailland
• 9Entrammes
• 9Évron

Hazards Listed by Municipality

Number of municipalities exposed to each natural hazard according to the departmental major risks file.

Hazards at a specific address on Géorisques