is metropolitan France safe from such a catastrophe?

Turkey and Syria continue to mourn their dead. Since Monday, the human toll of the powerful earthquake of magnitude 7.8, recorded near Gaziantep in the south-east of Turkey, continues to increase. This Wednesday, the authorities reported 11,700 victims to which must be added thousands of wounded and as many missing. Meanwhile, rescuers are busy assisting survivors amid the rubble and piles of rubble. Images of desolation far from unprecedented in this country particularly subject to the upheavals of the Earth. But what about the situation in mainland France? Are we also exposed to this type of natural disaster?

In the opinion of many specialists, the answer is clearly negative. “The situation in mainland France is very far from that of Turkey because we have no plate limit nearby”, explains Vincent Rebour, specialist in natural hazards at the Institute for Radiation Protection and Nuclear Safety. An earthquake results in fact from a sliding movement between two plates which can generate ruptures at the level of the faults which delimit these plates. The south-east of Turkey was therefore the victim of a crack on the fault separating the Eurasian and Anatolian plates.

The seismic hazard remains present in France

“The large limit of plates closest to French territory is located at the level of the Maghreb”, recalls the seismologist Jérôme Vergne. Or more than 1,000 kilometers from the territory of the metropolis. If several micro-plates still come together near France, especially on the Italian side, their movements relative to each other are not likely to generate a major earthquake. “The earthquakes will be all the larger and closer together as the sliding speed of the blocks around the fault is high. In France, the speed that is measured is less than one millimeter per year”, specifies Jérôme Vergne.

However, France is not totally protected from seismic hazards. Witness the Teil earthquake in Ardèche, of magnitude 5.4, responsible for building collapses and significant material damage in 2019. “Once a year, we can have an earthquake more widely felt, with a magnitude higher than 4. This can result in a few cracks in the walls or a few tile falls”, indicates Jérôme Vergne. In France, the most powerful earthquakes rarely exceed magnitude 6 and only occur very rarely. “Overall, it’s every 50 to 100 years,” said the seismologist.

Most of the time, these earthquakes take place in the eastern part of the country due to the proximity of a plate boundary. Other regions can however be affected, sometimes in rather mysterious ways. “We also note seismicity in Brittany or in the Massif Central. However, we are far from the plate boundaries and at this stage, we do not really have an explanation as to the presence of this seismic activity in these places. “, concludes Jérôme Vergne.