The collapse of the cliff at Delimara on Sunday was recorded by the seismic station, the University of Malta said today.

A man is in critical condition after the boat he was on was hit by rocks which tumbled down the cliff.

In a statement, the seismic station at Wied Dalam, Birzebbugia, operated by the Seismic Monitoring and Research Group within the Department of Geosciences, University of Malta, recorded a strong signal at 16:58 local time (14:58 GMT), yesterday, at the same time as the cliff face collapse at Delimara. 

The signal was also recorded at the seismic station installed at the University, Tal-Qroqq.  The SMRG operates a third station in Gozo, which did not record the signal. 

The signal appears not to be due to an earthquake but to the impact of the cliff face collapsing on the shore below. A series of small earthquakes occurred last week off the southern coastline of Malta, but it is not likely that there is a relation between these two occurrences.