Skip to main content
Français

La Réunion (974)

Saint-Joseph: geology and natural hazards

What public services say about the ground beneath the commune (population 39,207) and the hazards it faces: natural disasters, earthquakes, radon, cavities, clays, groundwater and rocks.

Hazard names and other data are quoted as their producers publish them, in French.

Explore the commune on the map

Saint-Joseph at a glance

Seismic zone
2 of 5 (low)
Radon potential
Category 1 of 3 (low potential)
Recognised natural disasters
17 since 1993
Underground cavities recorded
9
Ground movements recorded
108
Risk prevention plans
2

Hazards listed by the French State

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

  • Inondation
  • Mouvement de terrain
  • Séisme
  • Eruption volcanique
  • Feu de forêt
  • Phénomène lié à l’atmosphère: cyclone / ouragan (vent)
  • Transport de marchandises dangereuses

Recognised natural disasters

17 events recognised as a natural disaster by ministerial order since 1993.

  • Inondations et/ou coulées de boue: 15
  • Mouvement de terrain: 3
  • Chocs mécaniques liés à l’action des vagues: 2
  • Vents cycloniques: 1

  1. Vents cycloniques

    Event from 26/02/2025 to 28/02/2025, order published in the Journal officiel on 31/03/2025.

  2. Inondations et/ou coulées de boue

    Event from 28/01/2024 to 29/01/2024, order published in the Journal officiel on 07/04/2024.

  3. Inondations et/ou coulées de boue, Chocs mécaniques liés à l’action des vagues

    Event from 13/01/2024 to 15/01/2024, order published in the Journal officiel on 23/01/2024.

  4. Inondations et/ou coulées de boue

    Event from 02/02/2022 to 04/02/2022, order published in the Journal officiel on 13/02/2022.

  5. Inondations et/ou coulées de boue

    Event on 28/08/2021, order published in the Journal officiel on 05/11/2021.

  6. Inondations et/ou coulées de boue

    Event from 23/04/2018 to 24/04/2018, order published in the Journal officiel on 22/06/2018.

  7. Inondations et/ou coulées de boue

    Event from 17/01/2018 to 18/01/2018, order published in the Journal officiel on 01/02/2018.

  8. Inondations et/ou coulées de boue

    Event from 02/01/2014 to 03/01/2014, order published in the Journal officiel on 18/01/2014.

  9. Inondations et/ou coulées de boue

    Event on 02/01/2014, order published in the Journal officiel on 18/01/2014.

  10. Mouvement de terrain

    Event from 31/12/2013 to 03/01/2014, order published in the Journal officiel on 26/04/2014.

  11. Inondations et/ou coulées de boue

    Event from 02/01/2013 to 03/01/2013, order published in the Journal officiel on 25/04/2013.

  12. Inondations et/ou coulées de boue

    Event from 05/04/2009 to 07/04/2009, order published in the Journal officiel on 01/07/2009.

  13. Inondations et/ou coulées de boue

    Event from 24/02/2007 to 26/02/2007, order published in the Journal officiel on 28/03/2007.

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

    Event from 22/01/2002 to 23/01/2002, order published in the Journal officiel on 18/04/2002.

  15. Inondations et/ou coulées de boue

    Event from 10/02/1994 to 12/02/1994, order published in the Journal officiel on 23/04/1994.

  16. Inondations et/ou coulées de boue

    Event from 27/02/1993 to 03/03/1993, order published in the Journal officiel on 27/06/1993.

  17. Mouvement de terrain, Inondations et/ou coulées de boue, Chocs mécaniques liés à l’action des vagues

    Event from 18/01/1993 to 20/01/1993, order published in the Journal officiel on 12/06/1993.

Earthquakes and radon

Seismic zone

Zone 2 of 5: low. This regulatory zoning, in force since 2011, sets the rules for earthquake-resistant construction.

Radon potential

Category 1 of 3: low potential. The geological formations have the lowest uranium content. Radon is a naturally occurring radioactive gas that can build up in poorly ventilated rooms.

Beneath the town hall

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

Cavities and ground movements

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

9 underground cavities recorded (quarries, cellars, military works, natural cavities…).

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

See cavities and ground movements on the map

Risk prevention plans

  • PPR littoraux - Saint Joseph

    Natural risk prevention plan.

  • PPR Saint Joseph (i+mvt) 2017

    Natural risk prevention plan, under revision.

The zoning and regulations of each plan, which may prohibit or restrict building, can be consulted at the town hall and on Géorisques.

Nearby communes

Sources and limitations

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 03/11/2026. 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.