Situated in the Tien Shan mountain range, in the Kolsai National Park and classified as a biosphere reserve by UNESCO, Lake Kaindy offers a landscape as mysterious as it is spectacular, populated as it is by "ghost" trees. From its turquoise waters emerge the trunks of spruce trees (Picea schrenkiana) submerged during the formation of the lake, which has always aroused the interest of scientists and the wonder of visitors. Until now, researchers and the local population have attributed the formation of the lake to the 1911 earthquake, which caused major damage and numerous landslides in the region.
However, there are a number of reasons for this, a new study by researchers from IMBE and CEREGE have recently challenged this hypothesis, thanks to innovative research based on dendrochronology. This method makes it possible to go back in time by analysing the growth rings of trees and thus date events of the past. By comparing the tree-ring series of dead trees, submerged in the lake, with those of living trees on the surrounding slopes, the researchers were able to date the formation of the lake shortly after the autumn of 1888, thereby identifying another culprit: the Chilik earthquake that shook the same region on 11 July 1889, 22 years earlier than the generally accepted date.
With a magnitude of 8.2, this very large earthquake produced a cascading effect, destabilising a slope, causing a landslide, damming the river flowing through the valley and causing the trees to suddenly drown as the lake formed.
The study is not limited to revising the history of this emblematic landscape of Kazakhstan. It also confirms that Lake Kaindy lies in the epicentral zone of the 1889 earthquake and suggests that the surface ruptures described nearby are very probably linked to this event. By combining dendrochronological analyses with palaeoseismological research, this innovative work has improved our knowledge of the seismic risks in this region, which has been hit by several earthquakes since the end of the 19th century. It has also added to our knowledge of the region's natural heritage and contributed to efforts to preserve a unique, fragile and threatened environment.
With the Tien Shan mountain range still seismically active, the scenario highlighted at Lake Kaindy could be repeated, with a chain of natural hazards, but this time in heavily urbanised areas: such a cascading effect would then be likely to produce the greatest material and human losses.
