A reader took the picture (above) of cracks across the Azure window in Dwejra, Gozo, amid increasing fears that the rock might collapse.

The structure, a major tourist attraction, has been eroding rapidly. A large chunk of the left side of the rock crashed into the sea in 2012.

However in 2013, a geological rock assessment by the Environment Ministry said the structure is not facing imminent collapse but further erosion is “inevitable”.

The three-month study, conducted by local firm Geoscience Consulting Ltd, concluded that sea erosion did not threaten the window’s immediate structural integrity as had previously been postulated.

“It is safe to say that the Azure Window is not facing any imminent collapse as was previously believed. This still doesn’t mean it will last forever – this is a process,” the consultancy’s head geologist Peter Gatt had said.
 
The report estimated that the structure was midway towards becoming a ‘stack’, which is when the arch collapses and leaves an independent rock structure similar to the Fungus Rock.

The report dismissed previous recommendations for long metal bolts to be inserted into the rock formation as this could cause serious damage to the soft rock layer of the arch.

It said that, while the use of rock bolts would cause less damage, the “precarious location” of these blocks made it a hazardous solution.

Dr Gatt advocated using no structural support mechanisms and instead called for crack meters to be installed along the structure to regularly monitor the progress of erosion. 

The structure consists of two main rock layers: Upper Coralline Limestone, a hard, durable stone, and Blue Clay Limestone, a softer, malleable stone susceptible to erosion.

As much as 90 per cent of the outer layer is estimated to have eroded over the past 30 years, but Dr Gatt maintains that the second layer will be less susceptible. 

The picture was taken by Paul Vincenti.

The 'Azure window@ after the latest major collapse in 2012.