Expert comments on new karst collapse near Kazan
Sobakinskie Yamy, a chain of lakes in Zelenodolsk Municipal District, has long been a place of karst collapses. The latest one, from several days ago, covers 200 square meters and is 10 meters deep.
Ayrat Latypov, Associate Professor of the Department of General Geology and Hydrogeology, explains,
鈥淭he main mechanism behind the collapse is that unstable karst rocks, such as limestone and dolomite, are near the surface here. They are not only water-soluble but also covered by a web of fractures. Rainwater and meltwater slowly remove soil from this territory. The process is more active during spring flooding, with snow melting and heavy showers. Fluctuations of the water levels in the nearby Volga River also speed up the process. It seems that a critical mass of soil had been amassed, and hollow zones formed underground. The land mass with significant amounts of snow cover became too heavy and led to this collapse.鈥�
The scientist says that this is not the end of the story for this particular collapse,
鈥淭here are fractures on the edges of this crater. Seems like it may grow further. The walls of this collapse zone are steep and unstable. During the next stage, they will collapse, too, and become more reclined; at the same time, the crater will become deeper. As for whether the lake will appear here, that depends on the permeability of local layers. Keeping in mind that there are clay sections here, the surface water will slowly filter down here and form a water body.鈥�
As the interviewee assures, karst collapses can be predicted.
鈥淚f such a service is commissioned, a geologist can contour danger zones. However, there are no buildings or structures in this part of the district, so such surveys are not conducted here. One way or the other, karst processes are considered very dangerous because of their abruptness 鈥� one minute there are no indicators, and the other minute you have a collapse.鈥�
The lakes that already exist here have appeared as results of similar collapses. According to Dr. Latypov, it may well be transformed into a tourist attraction. In general, Tatarstan is not considered an active karst territory, so such events attract understandable attention of both the general public and researchers.