General seismic risk in France is categorised on a five-point scale, with zone 1 being very low risk, through to zone 5 in areas with a 'very strong' risk. In Metropolitan France the areas of highest risk are rated at 4, 'strong', and are located in the Pyrenees, Alps, the south of the Haut-Rhin "département", the Territoire de Belfort and a few communes in Doubs. A new zoning map comes into force on 1 May 2011, which significantly increases the rating for many areas. The major nuclear research facilities at Cadarache are located in a zone 4 area near the fault that caused the 1909 Lambesc earthquake, while the Marcoule research centre and the nuclear power plants at Tricastin, Cruas, Saint-Alban, Bugey and Fessenheim (near the fault that caused the 1356 Basel earthquake) are all within zone 3. A further 6 plants lie within zone 2.