A tsunami could soon hit major Mediterranean cities in or near the sea, such as Marseille, Alexandria and Istanbul, with almost a 100% chance of a wave reaching more than a meter in the next 30 years, according to Unesco.
The risk of a tsunami in Mediterranean coastal communities is expected to increase as sea levels rise. While communities in the Pacific and Indian Ocean, where most tsunamis occur, were often aware of the dangers, it was underestimated in other coastal regions, including the Mediterranean, Unesco said.
Now the United Nations Educational, Scientific and Cultural Organization said five communities at risk in the Mediterranean will join 40 other “tsunami-ready” towns and cities in 21 countries next year. In addition to Marseille, Alexandria and Istanbul, they include Cannes and Chipiona, a city on the Spanish Atlantic coast near Cádiz.
The moment the tsunami erupted off the Miyako waterfront from the Heigawa estuary after the great 9.1 magnitude earthquake of 2011 hit Japan. Photo: Mainichi Shimbun / Reuters
The tsunami-ready program is part of Unesco’s broader effort, launched ahead of next week’s United Nations conference on the oceans in Lisbon, to ensure that all communities at risk know what to do in the event of a tsunami in 2030.
“The 2004 and 2011 tsunamis were a wake-up call,” said Bernardo Aliaga, a leading tsunami expert at Unesco. “We have come a long way since 2004. Today we are safer. But there are gaps in the preparation and we need to improve; We need to make sure that visitors and communities understand the warnings. “
The 2004 deadliest Christmas 2004 tsunami in the Indian Ocean killed about 230,000 people in 14 countries, while the 2011 earthquake and magnitude 9.1 magnitude tsunami reaching almost 40 meters (130 feet) in height, they killed 18 people. Japan.
Since the 2004 Indian Ocean tsunami, the US-hosted Pacific Pacific Tsunami Warning Center has responded to 125 tsunami events, averaging seven a year.
map showing the first cities prepared for the tsunami in the Mediterranean region Unesco communities “ready for the tsunami” must develop a risk reduction plan, designate dangerous areas, show information and maps and raise awareness
“The upstream part is in good condition,” Aliaga said. “Work has been done to establish 12 tsunami warning centers covering most of the ocean, including the Mediterranean.”
Warning centers include five in the Mediterranean and the Northeast Atlantic, including Greece, Turkey, Italy, France and Portugal.
“The risk of a tsunami is underestimated in most areas, including the Mediterranean,” Aliaga said. “Events are rare and the risk does not translate from one generation to the next.
“We have to get the message across,” he said. “In the Mediterranean, there is no doubt: it is not if, it is when.”
One of the deadliest earthquakes in history hit Portugal on All Saints’ Day 1755, causing a 6-meter tsunami in Lisbon and Cádiz. As many as 50,000 people died in the quake, but many others were killed in the aftermath of the fires and tsunami.
An engraving depicting the Lisbon earthquake, fire and tsunami in 1755. Photo: Science History Images / Alamy
Tsunamis between 1.5 and 2 meters high can lift cars off the ground, while smaller waves can cause water walls to travel at 40 mph (65 km / h).
“The warning is not the whole story,” Aliaga said. “The second part is preparing the community: how people behave and react. This has a way to go.”
He cited the case of Tilly Smith, a 10-year-old British girl who took 100 people, including her family, to a safe place during the 2004 tsunami. Her geography teacher at school had told her that evacuate immediately when the water recedes.
Rising sea levels, which increase the impact of tsunamis on coastal communities, are “one more reason to increase the pace of our work,” he said.
“The link is that rising sea levels are increasing the impact of tsunamis.”
Tourists start running to the ground when the first of six tsunamis starts rolling towards a beach near Krabi, southern Thailand, in 2004. Photo: AFP / Getty
A 2018 study modeling tsunamis in Macau, China, found that rising sea levels increased the risk of tsunamis as they could travel further inland. The study found that the frequency of tsunami-induced floods increased from 1.2 to 2.4 times for a 45 cm rise in sea level and from 1.5 to 4.7 times for an increase of 90 cm.
Authorities in Alexandria, Istanbul, Marseille, Cannes and Chipiona are working on a “tsunami-ready” preparation, including evacuation signs and procedures, as well as plans to warn tourists, Aliaga said.
“We want 100% of communities, where there is a proven danger, to be prepared to respond by 2030,” he said. “They will have evacuation maps, they will have exercised and they will already have 24-hour alerts.”
The alerts were triggered about 10 minutes after an earthquake, he said, and could take the form of anything from loud messages to WhatsApp messages.
“If it’s a local tsunami, you have a maximum of 20 minutes before the first wave arrives. The second wave is larger and arrives 40 minutes after the first. You still have a chance to escape. “
Vladimir Ryabinin, Executive Secretary of the Unesco Intergovernmental Oceanographic Commission, said: “More than 40 communities in 21 countries are safer now that they have implemented our tsunami-ready program. If we are to meet this global challenge this year 2030, we need to expand our program very quickly. “