China News Service, Chengdu, September 11 (Reporter He Shaoqing) "Before we were rescued by helicopters, our researchers on Gongga Mountain photographed the scene of an ice avalanche in Hailuogou Glacier Icefall." Chinese Academy of Sciences Chengdu Mountain Disaster and Environmental Research Liu Qiao, a researcher at the Institute (referred to as "Chengdu Mountain Institute of the Chinese Academy of Sciences"), said in an exclusive interview with a reporter from Chinanews.com on the 11th that at present, it seems that the scale of the ice avalanche of the Hailuogou Glacier during the Luding earthquake was not large, and the ice waterfall was under a longer range. The flat ice tongue area has a good buffer for the movement of ice and snow materials that have collapsed, and the preliminary assessment is that the ice avalanche is less likely to cause disaster or further form a disaster chain.

　　It is understood that there are 74 modern glaciers in the Gongga Mountain area, with a total area of ​​about 200 square kilometers. .

In order to find the secret of the succession of nature, the Chinese Academy of Sciences has set up the Gongga Mountain Alpine Ecosystem Observation and Experiment Station in the Gongga Mountain jungle where the Chengdu Mountains are located.

In the past 40 years, generations of researchers have alternated relays at the test station, capturing the changes in the alpine climate, glaciers and forest ecosystems like "sentinels".

　　Liu Qiao, who has worked at the test station for 17 years, said that large-scale marine glaciers including Hailuogou Glacier, Mozigou Glacier, Yanzigou Glacier and Gongba Glacier developed around the main peak of Gongga Mountain.

In the hot summer, the melting of glaciers is accelerated, which is an intensive period for scientific research and observation activities of scientific researchers.

Although it was already autumn when the Luding earthquake occurred, due to the large-scale high temperature in Sichuan, there are still scientific research teams conducting observations in Gongga Mountain.

Comparison of Sentinel-2 images before and after the earthquake upstream of Mozigou Glacier.

Photo courtesy of the Chinese Academy of Sciences

　　Research by the Chinese Academy of Sciences shows that from 1990 to 2020, the glaciers in the Gongga Mountains continued to retreat, and the total area of ​​glaciers decreased from 237.8 square kilometers to 206.9 square kilometers, a decrease of 12.9%.

The Hailuogou Glacier, a representative glacier on the eastern slope of Gongga, has recently shown an accelerated loss trend. From 2016 to 2020, the glacier tip retreated at a rate of more than 50 m/year, and the thickness of the ablation zone decreased at a rate of 2-3 m/year. From 2018 to 2021 The average annual thinning of the ice tongue segment is 14 meters, and its accelerated degradation trend is more significant than that of continental glaciers in western China.

　　"Glacier changes in Gongga Mountain are mainly affected by the continuous impact of global warming, but it should be noted that there is a time lag process in the response of glaciers to climate change. At present, the glaciers in Gongga Mountain reflect the accumulation of climate change in the past ten years. Influence." Liu Qiao introduced that the geological disasters that have occurred many times in the history of the Gongga eastern slope are related to the strong retreat of the glaciers and the intensification of the erosion of the glaciers.

　　The epicenter of the Luding earthquake was located near the Hailuogou No. 1 camp, about 18 kilometers away from the main peak of Gongga Mountain in a straight line, and closer to the Hailuogou Glacier and Mozigou Glacier on the east slope.

According to the comparative study of Sentinel-2 images before and after the earthquake, it is also suspected that several ice/avalanche traces appeared in the upper reaches of Mozigou Glacier on the north side of Hailuogou Glacier.

　　At present, due to the serious damage to Hailuogou's access road due to the earthquake, it is difficult to get through in the short term, and it is impossible to enter the site to carry out a detailed assessment of the impact of glacier changes; the recent continuous cloudy and rainy weather in the region also restricts the observation of glacier dynamics by visible light remote sensing.

　　Liu Qiao pointed out that according to the data of multiple surveillance cameras deployed around the glacier at the observation station before the earthquake, there was a snowfall event from September 4th to 5th in the area above 3,000 meters upstream of the Hailuogou Basin. , the melting process of ice and snow in the upper reaches of the earthquake area should be intensified before and after the earthquake, and the disturbance of the ice edge instability and landform should increase.

In the later stage, continuous monitoring is required, and combined with field investigations, a comprehensive assessment of the superimposed effects of catastrophic provenance and water source changes that may be caused by glacier anomalies on the disasters in the earthquake area.

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