Collapse of Azure Window “unavoidable”

Malta’s Environment & Resources Authority (ERA) said several studies by experts had and all indicated that the collapse of the Azure Window was an unavoidable natural event. The collapse happened in storms overnight and was discovered on Wednesday morning.

“The collapse is most probably the compounded result of the process of natural erosion coupled with the strong winds hitting the islands and the related sea currents,” said the ERA.

A study carried out by Geoscience Consulting in 2013 described the arch as two layers of rock that behave differently, with around 90% of the lower layer collapsing in the last three decades. However it said these collapses had not impacted the stability of the arch because the layers are separated by a distinct bedding plane.

It said: “The present arch is experiencing rock fall along the flanks of the arch. This process involves boulders less than 1m large and poses a geohazard to visitors. However, the stability of the arch is not at risk. The ratio of width of span to thickness of arch is comparable to other natural arches worldwide which are deemed to be stable.”

However the report said that the lifespan of natural arches is short in terms of a geological time scale.

It ruled out stabilising the arch using large rock bolts because there was not enough stable rock on which to attach them. Smaller bolts were also difficult to install as “precarious location of these blocks and the installation of machinery over the arch make this type of intervention dangerous.”