A disaster plan was in place should a tsunami strike Malta, the Civil Protection Department said, assuring people it was prepared for such an eventuality.

Four scientists from the University of Portsmouth last week warned of the probability of a tidal wave hitting the island after they found evidence that, in the past, they had swept over Malta’s northeast coasts.

The CPD said it had a disaster master plan catering for such eventualities and it was also conducting a national risk assessment.

It must be stressed that the chance of such an occurrence is very small and there is no cause to raise false alarms

If a tsunami ranked as one of the highest risks, once the assessment was completed, resources would be dedicated to inform people accordingly, a spokesman said.

“However, expert advice indicated that tsunamis occur when earthquakes exceeded seven on the Richter scale and the resultant wave depended on a number of factors,” he said.

“An earthquake of that magnitude in the Mediterranean will have consequences on Malta and might cause problems on its own. Any tsunami wave that is big enough to affect Malta will impact the islands some time later, possibly even hours, depending on the point of origin.”

Studies on the upper shore immediately north of the White Tower on the NE Marfa ridge.

The CPD has, therefore, started discussions with the University of Malta for inclusion in a Mediterranean-based tsunami early warning system, available online.

Signs indicating an incoming tidal wave included earthquakes and the retreating of the shoreline. Those living near the shoreline should seek shelter in the top floors of buildings or reach for higher ground, the spokesman said.

However, since Malta and Gozo are islands, a tsunami could come from any direction and action depended on this.

“Preliminary indications suggest that a tsunami originating from the south will have negligible impact on the islands given that they are protected by the relatively high cliffs.

“A tsunami from the north will have a greater effect and may cause severe flooding without the initial wave impact because the distance between Sicily and Malta is not such to allow the wave to develop fully.”

Of more concern are tsunami waves from north-northeast, northeast or east because there is ample distance for the wave to develop before hitting our shores.

This was also reflected in yearly storms where those coming from the gregale had a much more severe impact, he added.

“This said, it must be stressed that the chance of such an occurrence is very small and there is no cause to raise false alarms and the matter must be treated with caution and not alarmism,” the spokesman insisted.

He added that if a tsunami wave hit Maltese shores, considerable debris would be carried inland. Rescuers would not be able to reach people until the waters receded and air rescue was limited worldwide.

Once waters receded, the scenario would be very similar to that following an earthquake, so most simulation exercises carried out by the CPD consisted of earthquake scenarios. Still, last year, 20 rescuers went to Salerno for an EU-funded tsunami exercise and simulations will be carried out in the coming months.

The CPD comments come after the University of Portsmouth scientists published a paper saying they had found geological evidence that historic tsunami waves swept over Malta’s northeast coasts reaching 20 metres above sea level in some places. When the waves actually hit the Maltese shores so far remains unknown.

When contacted, Malcolm Bray, who led the study, said the research focused on evidence of past tsunamis but they did not undertake risk assessments.

While stressing that these were personal views based on his experience, he said the areas most likely to be at risk would be situated on the northeast or north-facing coast.

Asked about the effect of a tsunami on the reverse osmosis plant off Ċirkewwa, he said this was partly sheltered by its position at the western entrance to the south Comino channel and by the fact it was on higher ground, inland above the road. The plant off Pembroke was exposed to the east and northeast but was situated on slightly higher ground and over 100 metres inland.

The Delimara power station is, according to Dr Bray, also sheltered from the northeast and east by Delimara Point but a tsunami from the east or northeast would still enter the bay where it is situated.

Referring to the study carried out by the four scientists, Dr Bray said their Maltese research collaborators, led by John Schembri from the Department of Geography, provided valuable local expertise but did not participate in any assessments of tsunami risks.