The coastal tower at Ghajn Tuffieha is in danger of collapse because the cliff face it is perched on is retreating, according to PhD research.
Popeye Village has also been found to be built on landslides, which are moving.
The study, Investigation Of Lateral Spreading Phenomena Along The Northwest Coast Of Malta And Implications Of Landslide Hazard, is being conducted by Odette Magri, a full-time assistant lecturer within the Geography Division of the Mediterranean Institute at the University of Malta.
It aims to monitor any landforms that have been detached along the northwest coast of Malta, using the GPS technique.
The northwest coast is the subject of the study because it is frequented by tourists and locals who are not aware of the danger posed by the coastal landslides, Ms Magri said. These include rock falls as well as mud slides on the clay slopes in winter.
Precarious movement has been registered at Ghajn Tuffieha's coastal tower, built by Grand Master Lascaris in 1637 for defence purposes.
Popeye Village, situated on landslides found to be moving, poses a danger to visitors, she said, pointing out that it is a main tourist attraction and frequented by children.
The landslides are being monitored and while movements are minimal (centimeters), they are still dangerous because it is not known when they can collapse, or trigger rock fall.
Behind the houses of Popeye Village are massive blocks that, centuries back, had been detached from the plateau above and fallen. But benchmarks on them have detected movement, she said.
"Even if it is slight, they are still moving and had never been monitored before. No one knows when rock fall can occur, but it is certain that it would have serious consequences," she said. She referred to an incident in the summer of 1979 when clay, which was not even wet, on the southern cliff of Golden Bay, collapsed when it was full of people.
"Fortunately, no one was injured, but the consequences could have been serious," Ms Magri noted.
It is the third and final year that Ms Magri is working on the study, which has encountered its fair share of problems, she maintains.
In September 2005, a GPS network, consisting of 24 benchmarks (10cm steel rods) was installed at three sites: Il-Prajjet (Popeye Village), Rdum id-Delli close by, and Ghajn Tuffieha bay. However, a number of them have gone missing, with data going "down the drain".
Ms Magri will produce hazard maps to assess the degree of danger in these areas.
The research is a joint collaboration between the University of Malta, the Università di Modena e Reggio Emilia and the Consiglio Nazionale delle Ricerche in Padova. Monitoring is intended to be continued after Ms Magri's research is complete.
Her research will be presented at an Italo-Maltese workshop on Integration of the Geomorphological Environment and Cultural Heritage for Tourism Promotion and Hazard Prevention, which will be held at the Italian Cultural Institute over the next few days gathering a host of international speakers.
Ms Magri is also making a presentation in Malaysia in June, she said, pointing out the interest in the subject on the international scene, unlike in Malta.
The workshop was, therefore, also aimed at raising awareness of the subject, she said, adding that it was only now that warning signs were being installed to indicate the possibility of rock fall at Gnejna Bay, for example, and pointing out danger due to cliff retreat near the Ghajn Tuffieha tower.