Earthquake swarm south of Malta is nothing new with more than 100 tremors occurring in past days

You may have felt some of the earthquakes that struck to Malta’s south but they are just a tiny fraction of the regular tremors that occur in the area

The recent spate of earthquakes to the south of Malta is concentrated along the Melita Graben (Photo overlay: Geologist Peter Gatt)
The recent spate of earthquakes to the south of Malta is concentrated along the Melita Graben (Photo overlay: Geologist Peter Gatt)

A 5.2 magnitude earthquake felt on Tuesday evening may have created panic, coming hot on the heels of another tremor of similar magnitude a day earlier.

But the earthquakes that have been happening in the same zone between Malta and Libya over the past week are not a new phenomenon, according to seismologist Daniela Farrugia.

The area situated to the south of Malta is prone to earthquakes and there have been more than 100 tremors over the past few days, she tells MaltaToday.

“People only felt three because they were slightly closer to Malta and slightly higher in magnitude,” Farrugia says. “Malta is surrounded by geological faults that create tremors all around the Mediterranean.”

A fault is a zone of fractures or a fracture between two pieces of rock. Faults enable the blocks to move in relation to one another. This movement can occur quickly in the case of an earthquake, or slowly in the form of creep.

Asked if the current swarm of earthquakes could lead to stronger earthquakes and tsunamis, Farrugia adopts a cautious tone – seismologists cannot predict the future but use past experience to understand what the possibilities are.

“Nature is unpredictable. However, the University’s Seismic Monitoring and Research Unit (SMRU) has been conducting various geophysical studies over the past few years, and looking at history, no major earthquakes have ever occurred from that area,” she says.

Geologist Peter Gatt agrees that history might be a good predictor of what to anticipate from these zones.

“This earthquake swarm is occurring on a fault in the south-east of Malta, in a zone known as the Melita Graben,” Gatt explains.

He points to a map used by MaltaToday in its original report on the Tuesday evening’s earthquake, which shows the area of earthquake activity, and overlays the position of the Melita Graben on it. The red spots indicating the recent spate of earthquakes all fall within this geological feature.

At a depth of 1,731 metres the Melita Graben is located to the south of Malta. Parallel to this, on the eastern flank, is the Malta Escarpment, the prominent morphological feature offshore eastern Sicily that connects the deep Ionian basin with the Hyblean carbonate platform to the west.

This escarpment is to blame for the 1693 earthquake that devastated south-eastern Sicily, demolishing structures and killing about two-thirds of Catania's residents. The original Mdina cathedral was destroyed by the same earthquake.

“Malta has a history of earthquakes, so we should not be alarmed. Activity occurs, but it is not cause for alarm,” Gatt says.

The location of the current earthquake swarm, history suggests, should be of little concern even if the living room table suddenly starts sliding.