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Castres: geology and natural hazards

What public services say about the ground beneath the commune (population 42,505) 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

Castres at a glance

Seismic zone
1 of 5 (very low)
Radon potential
Category 3 of 3 (significant potential)
Recognised natural disasters
35 since 1982
Underground cavities recorded
2
Ground movements recorded
24
Risk prevention plans
3

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
  • Phénomène lié à l’atmosphère: tempête et grains (vent)
  • Risque industriel
  • Rupture de barrage
  • Transport de marchandises dangereuses

Recognised natural disasters

35 events recognised as a natural disaster by ministerial order since 1982.

  • Inondations et/ou coulées de boue: 19
  • Sécheresse: 16
  • Tempête: 1

  1. Sécheresse

    Event from 01/10/2023 to 31/12/2023, order published in the Journal officiel on 02/07/2024.

  2. Sécheresse

    Event from 01/07/2022 to 30/09/2022, order published in the Journal officiel on 03/05/2023.

  3. Inondations et/ou coulées de boue

    Event from 10/05/2020 to 12/05/2020, order published in the Journal officiel on 10/07/2020.

  4. Inondations et/ou coulées de boue

    Event from 14/10/2018 to 15/10/2018, order published in the Journal officiel on 08/11/2018.

  5. Inondations et/ou coulées de boue

    Event on 10/06/2018, order published in the Journal officiel on 20/10/2018.

  6. Inondations et/ou coulées de boue

    Event on 29/05/2018, order published in the Journal officiel on 20/10/2018.

  7. Inondations et/ou coulées de boue

    Event on 14/02/2017, order published in the Journal officiel on 07/07/2017.

  8. Sécheresse

    Event from 01/01/2017 to 31/12/2017, order published in the Journal officiel on 12/08/2018.

  9. Inondations et/ou coulées de boue

    Event on 23/06/2014, order published in the Journal officiel on 07/11/2014.

  10. Inondations et/ou coulées de boue

    Event from 30/05/2013 to 31/05/2013, order published in the Journal officiel on 13/09/2013.

  11. Sécheresse

    Event from 01/01/2013 to 31/03/2013, order published in the Journal officiel on 21/06/2014.

  12. Sécheresse

    Event from 01/01/2012 to 31/12/2012, order published in the Journal officiel on 25/05/2013.

  13. Inondations et/ou coulées de boue

    Event from 15/03/2011 to 16/03/2011, order published in the Journal officiel on 21/07/2011.

  14. Sécheresse

    Event from 01/01/2011 to 31/12/2011, order published in the Journal officiel on 17/07/2012.

  15. Inondations et/ou coulées de boue

    Event on 25/08/2009, order published in the Journal officiel on 14/01/2010.

  16. Inondations et/ou coulées de boue

    Event on 21/04/2009, order published in the Journal officiel on 20/08/2009.

  17. Sécheresse

    Event from 01/01/2009 to 30/09/2009, order published in the Journal officiel on 13/01/2011.

  18. Sécheresse

    Event from 01/01/2008 to 31/03/2008, order published in the Journal officiel on 22/04/2009.

  19. Sécheresse

    Event from 01/01/2007 to 31/03/2007, order published in the Journal officiel on 10/10/2008.

  20. Sécheresse

    Event from 01/01/2005 to 31/03/2005, order published in the Journal officiel on 10/10/2008.

  21. Sécheresse

    Event from 01/07/2003 to 30/09/2003, order published in the Journal officiel on 26/08/2004.

  22. Inondations et/ou coulées de boue

    Event from 05/06/2003 to 06/06/2003, order published in the Journal officiel on 27/06/2003.

  23. Sécheresse

    Event from 01/01/2002 to 30/09/2002, order published in the Journal officiel on 19/10/2003.

  24. Inondations et/ou coulées de boue

    Event from 12/11/1999 to 14/11/1999, order published in the Journal officiel on 18/11/1999.

  25. Inondations et/ou coulées de boue

    Event on 02/08/1999, order published in the Journal officiel on 04/12/1999.

  26. Sécheresse

    Event from 01/08/1998 to 31/12/1998, order published in the Journal officiel on 29/12/2000.

  27. Inondations et/ou coulées de boue

    Event from 06/12/1996 to 08/12/1996, order published in the Journal officiel on 23/02/1997.

  28. Inondations et/ou coulées de boue

    Event from 16/12/1995 to 17/12/1995, order published in the Journal officiel on 14/02/1996.

  29. Sécheresse

    Event from 01/10/1994 to 31/12/1997, order published in the Journal officiel on 29/07/1998.

  30. Inondations et/ou coulées de boue

    Event from 04/07/1992 to 06/07/1992, order published in the Journal officiel on 16/01/1993.

  31. Inondations et/ou coulées de boue

    Event from 09/06/1992 to 13/06/1992, order published in the Journal officiel on 16/01/1993.

  32. Sécheresse

    Event from 01/01/1992 to 30/09/1994, order published in the Journal officiel on 03/08/1995.

  33. Sécheresse

    Event from 01/05/1989 to 31/12/1991, order published in the Journal officiel on 18/11/1992.

  34. Inondations et/ou coulées de boue

    Event on 23/04/1988, order published in the Journal officiel on 23/10/1988.

  35. Tempête, Inondations et/ou coulées de boue

    Event from 06/11/1982 to 10/11/1982, order published in the Journal officiel on 19/11/1982.

Earthquakes and radon

Seismic zone

Zone 1 of 5: very low. 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.

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.

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

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

See cavities and ground movements on the map

Risk prevention plans

  • PPRi de Castres Révision

    Natural risk prevention plan, under revision.

  • PPR RGA départemental

    Natural risk prevention plan.

  • PPRT - SEPIPROD

    Technological risk prevention plan.

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.