Tsunami alert centre (CENALT) operational

Since the 1st of July 2012, the tsunami alert centre, known as the CENALT and operated by France, has been operational. The CENALT monitors strong earthquakes and tsunamis occurring in the Western Mediterranean and North-East Atlantic. In the event of the risk of a tsunami, the CENALT alerts the public safety authorities.


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Description of the CENALT

In 2009, The French Ministry for Ecology, Sustainable Development and Energy (MEDDE) and the Ministry of the Interior (MI) gave the French atomic energy commission (the CEA), in partnership with the French Navy's oceanographic and hydrographic service (SHOM) and the national centre for scientific research (CNRS) the task of creating and operating the tsunami alert centre (CENALT) in France. The CENALT is housed by the CEA, in Bruyères-le-Châtel (Essonne). The centre consists of an operations room, a data analysis room and offices.


From monitoring to the arrival of a tsunami generating phenomenon: CENALT procedure

In the CENALT's operations room, an operator analyses the seismic signals received 24 hours a day and checks the CENALT's operational capability. When a strong earthquake occurs in the Western Mediterranean or North-East Atlantic, within 1 to 3 minutes the system automatically detects the seismic waves and calculates the position of the earthquake, as well as its magnitude. The operator is immediately alerted, validates the automatic processing and, if necessary, applies a few corrections. He activates the tsunami arrival time computation software and the alert message formatting software. The operator then validates the messages that are transmitted to the French public safety authorities and to the other subscribing countries.


Provision of tide gauge data for the tsunami alert centre

The water heights measured by the tide gauges contribute to the sea level rise alert. This sea level rise alert aims to receive and process these tide gauge data downstream of the seismic data.

The confirmation that a tsunami has been induced by an earthquake is based on the sea level recordings from tide gauges located along the coast or from tsunami gauges located offshore. These measurements require prior processing of the water heights in order to subtract the astronomical tide.

If a tsunami is recorded by the tide gauges, the operator measures its arrival time and its amplitude and transmits a new message to the French public safety authorities.autorités françaises de sécurité civile.


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