The AFPS (Association Française du génie Para-Sismique) is in charge of France's national "emergency system" for carrying out building diagnostics in post-seismic emergency situations throughout the country, as well as internationally under specific intervention agreements. The Association also regularly organises post-seismic missions to provide feedback on actual events and develop expertise in earthquake engineering.
The technical objectives of the mission are divided into different sections:
- Seismology,
- Seismic movements for engineers and regulations,
- Soil behaviour,
- Behaviour of historic buildings,
- Small buildings and individual houses,
- Behaviour of large structures (hospitals, bridges, dams, power stations)
- Networks and industrial installations and Crisis management and reconstruction.
Following the events of 6 February 2023 in Turkey (two earthquakes of Mw 7.8 and Mw 7.5 less than 100 km apart), a mission was organised with the participation of some fifteen agents from various institutes and public bodies and private companies that are members of the AFPS. Cerema had the opportunity to take part, applying its expertise in dynamic in-situ measurements, both on the soil surrounding the rupture zones in order to characterise the amplification of the seismic movement, and on buildings and civil engineering structures (bridges, dams, historic monuments) in order to gain a better understanding of the effects of vibrations on the environment and buildings.
This post-seismic mission was carried out at the epicentre of the earthquakes, which occurred close to the surface (hypocentres at a depth of less than 20 km). Cerema placed sensors in various locations, including buildings, infrastructures and networks, to understand their behaviour and the displacement of the ground, and to estimate the response of buildings following the earthquakes, as well as their behaviour in the future. This information will be used to determine whether and how to rebuild on the same site.
The mission consisted of several visits to affected sites and meetings with Turkish academics and earthquake engineering professionals to gather as much information as possible. It was also an opportunity to meet local residents and hear their views on construction, standards, the impact of the earthquake, crisis management, etc.
This feedback will provide a wealth of data and useful information on the behaviour of structures, good building practice, the areas where the risks are greatest, and crisis management. A report is currently being drafted by the AFPS team and will be published and presented to the public at the end of September 2023.
In brief, a few figures from the campaign: a 250 km x 100 km area covered (Fig 1a) by 4 cars with more than 10,000 km travelled (cumulative) Fig 1b, more than 3,000 photos and 200 videos, and more than 800 MB of ambient vibration data recorded on site (ground and structures).
Ambient vibration measurements at the base of a slightly damaged building in the northern district of Adana.
Ambient vibration measurements using CEREMA equipment, Berke arch dam (north of Osmaniye, Turkey).
Surface expression of the fault > 1 m of sinister displacement, residential district of Kirikhan.