Satellite images could be distorted
Some of the posts are accompanied by side-by-side aerial pictures that allegedly compare the dam in 2009 and 2018. The 2018 photo shows the dam visibly skewed and warped, suggesting some structural problems.
The use of these images is misleading. Images like these are often taken from Google Earth, which is a mosaic of satellite and aerial photographs taken on different dates. Weather conditions, lighting, angles, and other factors affect each photograph, making the objects appear distorted.
The “distortion problem” is a common phenomenon, according to the NASA Earth Observatory.
Satellite images may not accurately represent the terrain because distortions caused by the smallest differences in camera positioning, for example, can affect the relative size and distance between features in the images.
Similar claims about the Three Gorges Dam were also shared widely last year in early July with aerial photographs.
At that time the China Aerospace Science and Technology Corporation (CASTC) released its satellite image on their Weibo account to show the normal condition of the dam.
Another aerial photograph of the dam taken by Xinhua News Agency in June 2019 from a much lower altitude shows no sign of distortion.
Expert dismisses the claim
Another claim circulating along with the satellite images this week is that a Chinese expert at the China Academy of Building Research named Huang Xiaokun, who is also the chief engineer and director of Research and Development Center of Construction Research Technology, used a Chinese social media application (WeChat) to share his “last warning” to those who live in the Yichang area near the dam, calling for immediate evacuation.
For example, this tweet features a screenshot of Huang Xiaokun’s post along with his qualifications. The same story was also shared by an article that gained 10,000 views in under 10 hours, although it has since been deleted.
However, a researcher at the China Academy of Building Research told Annie Lab that the post was not made by his colleague Huang Xiaokun.
The Academy has reported the incident to Weibo, which now labels it as “false information.”
In a media interview, Huang himself said the rumor “has nothing to do with me, nor do I know who that ‘Mr. Huang Xiaokun’ from Ningde, Fujian Province is.”
On Sunday, state-owned media CCTV-2 said the water level was approaching 147 meters, two meters above the flood control limit level.
The news seems to have prompted numerous rumors about the “imminent collapse” of the world’s largest dam.