19 March 2021
Tbilisi: a 500,000 cubic metre landslide, probabkly triggered by road construction
In Tblisi in Georgia, a 500,000 cubic metre landslide has developed on the edge of the metropolitan area, probably triggered by construction of a road. The landslide which is described in articles in both Vestnikkavkaza.net and JAM News, is impressive in scale:-
The image above shows a very large fissure that defines the mobile block. This appears to be sliding towards the left of the image, where the slope has been cut fro road construction. The image below provides a sense of the motion:
The under-excavation road is being protected from minor rockfalls by a barrier of what appears to be concrete blocks. This suggests that the movement has been developing for a few days at least.
The landslide has developed on the margins of a new road linking two residential areas of Tbilisi – Vashlijvri and Nutsubidze. I believe that the Google Earth image below shows the site. This image was taken in July 2020:-
“The earth may descend tomorrow, the day after tomorrow, or in a year, but it will definitely come down. Where and how – the issue of modeling, it needs to be assessed,” said Geologist Tea Godoladze, director of the National Center for Seismological Monitoring.
According to her, geologists and surveyors who have already made the initial assessment have come to the conclusion that cracks in the slope are the result of improper intervention in the environment. And, most likely, a landslide cannot be avoided.
The danger exists both in the immediate vicinity of the landslide and in other areas, since the support system is also broken there, said geomorphologist Lasha Sukhishvili.
“The speed of the landslide is still unclear. This can take years. But, for example, due to heavy rain or some vibrations, the process may speed up a little,” said Sukhishvili.
Managing a landslide of this scale will be challenging. I am reminded of the Rattlesnake Ridge landslide, where the pragmatic solution has been simply to allow it to move whilst monitoring it carefully.