‘We Know It Will Happen’: Inside France’s Red Alert Plan For The 15 Minutes After A Tsunami

Inside France's Red Alert Plan - Merchant Navy Info - News

Tucked away on the outskirts of Paris, France’s tsunami warning center is not far from the sea. But CENALT is the true epicenter of this country’s tsunami warning network. A place that could one day save thousands of lives. Tsunamis as large as the 2004 Indian Ocean tsunami. Which killed around 250,000 people, and are extremely rare. But they are more common than many people realize, including here in Europe. Approximately 100 tsunamis have occurred in the Mediterranean Sea and its associated waters since the beginning of the 20th century. This corresponds to about 10% of the total number of infections recorded during the same period. Northeast Atlantic tsunamis are rare but still account for about 5% of all tsunamis. There was one particularly tragic event.

1755 Lisbon Earthquake

The strongest tsunami we know of in the Atlantic Ocean. Was caused by the Lisbon earthquake of 1755,” he said of the National Coordination of CENALT (short for Center d’ALerte Tsunami) says official Hélène Hébert. This earthquake has a magnitude of about 8.5. Which she explains is similar to the france earthquakes she sees several times a century in the Pacific Ocean. But extremely rare in the Atlantic Ocean. Although the coast of France was mainly protected by the Iberian Peninsula. The tsunami destroyed large parts of Lisbon and Cadiz, as well as parts of Morocco. Causing thousands of casualties.” As a result, The waves reached south-west Cornwall and Ireland. “This is a massive tsunami that is expected every 3 to 5 centuries. So it could happen tomorrow. Or it could happen in the next century, but we don’t know it’s going to happen.

Tsunami Warning Within 15 Minutes

Although most tsunamis tend to be much smaller, they can still have devastating consequences and lead to loss of life. That’s why CENALT’s work is so important. The center will celebrate its 10th anniversary in 2022. It was established after the 2004 tsunami as part of UNESCO’s broader efforts. To establish tsunami warning systems around the world. It is housed in a state-of-the-art building, operates 24/7, and is managed by a team of geophysical data analysis experts from the CEA (French Alternative Energy and Atomic Energy Commission).

So There Are Two Main Purposes

First, it detects earthquakes that can cause tsunami warning or alerts the relevant authorities within 15 minutes.

Second, it tells us whether there will be a tsunami and, if so, how long and with what amplitude it will arrive.

Initial information comes from a network of hundreds of seismic stations. Each is displayed on a giant screen in the main gallery and transmits data each time a tremor occurs. Events are assigned one of three threat levels (yellow, orange, or red) depending on their severity, and a corresponding alert is sent. The corresponding tide level is also monitored to determine the sea level.

How Does Tsunami Detection Technology Work?

If one of the seismic stations flashes red, it means it has detected a signal,” explains Pascal Rudil. CENALT’s technical coordinator. The station may have simply felt strong winds or a passing truck. However, if multiple observation points start blinking at the same time. It means that they are being affected by fairly strong seismic waves. In other words, an earthquake. The system then attempts to find the epicenter of these discoveries. And adds the information on the map in the form of a circle. The size of the circle indicates thickness, and the color indicates depth. 

“Tsunamis can arrive very quickly, so our goal is to alert the relevant authorities within 15 minutes,” he added. “If an earthquake occurs in the western Mediterranean, for example, near Algeria, the earthquake will cross the ocean within an hour and 15 minutes.

 So there is not much time left. “The tsunami in our country is not as large as the tsunami in the Pacific, but Waves 30 meters high are not high enough to cause damage or injury. Even 50 cm is dangerous for swimmers.

What Is The Risk Of A Tsunami In France?

Fortunately, at least so far, there have been no major incidents in CENALT. From its inception to 2022, the  Center has issued 84 “information level” warnings (no tsunami threat) and only two “warning level” warnings (shore waves less than 1 meter). The last time it was issued was in 2022. March In 2021,  sea levels in Toulon rose by approximately 5 centimeters. But we also know that it’s only a matter of time. The French Riviera is probably one of the most dangerous regions in mainland France. Côte d’Azur is probably one of the most dangerous regions on the French mainland, and the greatest threat comes from the North African coast,” says Hébert. The 4,444 cities and municipalities on the Côte d’Azur, which is popular with tourists, are also making preparations. Cannes has set up digital transformation points, and Antibes is conducting evacuation drills. 

“The waves are not expected to be 20 meters like in Japan, Chile, and Sumatra, but rather 1-2 meters,” adds Hebert. However, what is extremely dangerous is not only the height of the tsunami but also the potential for damage to coasts, ports, and roads due to ocean currents, currents, and coastal flooding. ” While he is rightly proud of his commitment to CENALT over the past ten years, he is by no means standing still. Although technology has come a long way, they are interested in continuing their own research, especially since rising water levels due to the climate crisis could make the situation even worse.

Impact Of The Climate Crisis 

“Water level does not affect the earthquake tsunami warning itself, but earthquakes can occur regardless of sea level, so the impact on the coast can certainly have an impact,” Hebert said. To tell “If the waterfront is very low in a small port, for example in Cannes or Toulon, tsunamis can be even more dangerous.“Therefore, numerical simulations can be used to make real-time predictions for the next few years. It would be great if we could do that like we’re doing now with the weather.’For example, for a particular event in Nice, to predict that  we can expect 3.5 million people, Marseille, about 500,000 people, etc.’ There’s another reason why  CENALT undoubtedly remains at the forefront of tsunami warning technology. And not just for the next ten years, but for many more.

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