The year is 365AD. Saturday, July 21. Just after sunrise, a four-metre wave could be seen coming towards Marsaxlokk. The ‘harbour wave’ crashed along the northern Maltese coastline, after travelling around 800 kilometres across the Mediterranean. Its source, an underwater earthquake of magnitude eight, occurred about one a half hours before in the eastern Mediterranean with an epicentre near Crete.
The last significant tsunami to hit our shores was on Monday, December 28, 1908. This was caused by a large earthquake near Messina, causing flooding in coastal locations such as Msida and Birżebbuġa. Although the tsunami devastated Messina and Reggio Calabria, no lives were lost on the Maltese islands.
Eliminating or predicting these tsunami events is not possible. The best defence is an early warning system that detects the large wave and autonomously alerts people in coastal areas to move to higher grounds. These systems rely on a network of sensors that upload sea-level gauge data to a central server at a high temporal frequency. Intelligent software is then used to monitor the records being sent from different countries to detect any anomalies in the trends. Due to the closed shape of the Mediterranean basin and the relatively close proximity of tsunami-generating sources, warnings cannot be issued hours in advance. However, when you have to ‘run for your life’, every second counts.
The Seismic and Physical Oceanography research groups within the Department of Geosciences, University of Malta, coordinated by Prof. Pauline Galea and Prof. Aldo Drago respectively, have already simulated typical scenarios to identify the most vulnerable coastal areas around the island.
Now, in collaboration with the Civil Protection Department (CPD) and the Joint Research Centre (JRC) of the European Commission, the infrastructure for the monitoring of sea level around the island, is being enhanced. Stations in Ċirkewwa, Marsaxlokk and Delimara are already online and transmitting data to a global database of measurements from more than 700 stations. The raw records are sent to the University of Malta where they are further quality controlled and used for the delivery of local downstream services.
Later this year, as part of the JRC-coordinated Tsunami Last Mile project, information panels will be installed in Marsaxlokk to raise awareness and give real-time updates about the state of the sea. These devices will also provide authorities with the hardware to issue alerts and warnings in the unlikely (but possible) event of a tsunami. The announcement system on these panels may also be automatically triggered if sensors detect an anomalous rise or fall of the sea level. Education is also crucial and CPD will be organising a simulation exercise that will involve all local emergency response entities.
During the event, the system will be triggered to test the panels, loudspeakers and sirens, and a section of the community will be evacuated from their homes to nearby assembly areas. The stakeholders involved will receive warning text messages and their reaction time will be monitored. Hopefully, this exercise will serve to test, train, and, where possible, improve on the respective emergency management procedures.
Dr Adam Gauci is a lecturer with the Department of Geosciences of the Faculty of Science at the University of Malta and is responsible for ocean observations carried out by the Physical Oceanography Research Group.
Did you know?
• The word Tsunami comes from Japanese: tsu = wave; nami = harbour.
• In the ocean, a tsunami does not affect ships at sea, where tsunami waves might be 30cms high. A ship might notice a slight swell and nothing more.
• About 80 per cent of the tsunamis occur in the Pacific Ocean’s Ring of Fire.
• Prior to the 2004 deadliest tsunami, there was no warning system in the Indian Ocean, demonstrating the importance of these early warning systems in coastal areas.
For more trivia see: www.um.edu.mt/think
Sound bites
• Molecular clock evolutionary analysis is being used to determine how long SARS-CoV-2 existed before the reporting of the first cases in December 2019. The technique uses the mutation rate of genes to deduce when two or more life forms diverged. The study estimates that the common ancestor of all variants of SARS-CoV-2 existed undetected for at most two months before the first COVID-19 cases.
https://www.sciencedaily.com/releases/2021/03/210318185328.htm
• Neanderthals, our closest ancestor, had the capacity to perceive and produce human speech. The evolution of language and Neanderthals’ linguistic capacities are long- standing questions in human evolution. Ongoing research relies on fossil evidence using CT scans and finding a similar ear structure to modern humans.
https://www.sciencedaily.com/releases/2021/03/210301112358.htm
For more soundbites listen to Radio Mocha www.fb.com/RadioMochaMalta/