Chinanews.com, Beijing, August 7 (Reporter Sun Zifa) On the eve of the 3rd anniversary of the Jiuzhaigou M7 earthquake, researcher Fu Bihong, Institute of Aerospace Information Innovation, Chinese Academy of Sciences and UNESCO International Center for Natural and Cultural Heritage Space Technology (HIST) The team released the latest remote sensing monitoring and evaluation on the 7th, showing that after three years of restoration and reconstruction after the disaster, the water environment of Jiuzhaigou has gradually recovered, but tourism activities still need to prevent geological disasters.

Water distribution map in the core area of ​​Jiuzhaigou. Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

Comparison of remote sensing images after the Wuhuahai earthquake (August 10, 2017, left) and after nearly three years of restoration (June 9, 2020, right). Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

  On August 8, 2017, a magnitude 7 earthquake occurred in Jiuzhaigou, causing huge damage to the Jiuzhaigou World Natural Heritage Site. After Jiuzhaigou’s post-disaster restoration and reconstruction, Fu Bihong’s team used multi-source, multi-temporal, multi-scale remote sensing monitoring, combined with field scientific investigations, and recently completed the restoration and reconstruction 3 years later (2017-2020) the core of Jiuzhaigou World Natural Heritage Site The area’s topography, water body, vegetation coverage and other elements are "sky-space-ground" integrated remote sensing monitoring and evaluation.

The water landscape of the Panda Sea and the Jianzhu Sea: Comparison of remote sensing images before the earthquake (August 1, 2015), immediately after the earthquake (August 10, 2017), and two years after the earthquake (August 16, 2019) ( from left to right). Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

  The remote sensing evaluation results show that the restoration and reconstruction of Jiuzhaigou 3 years after the disaster has achieved initial results, and the water environment in the core area of ​​Jiuzhaigou World Natural Heritage Site is gradually recovering its former style, but tourism activities in the heritage site still need to prevent geological disasters such as landslides, collapses and mudslides. .

Comparison of water images in Jinghai: just after the earthquake (August 10, 2017, left); nearly three years after the earthquake (June 9, 2020, right). Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

  The research team's interpretation of the water body through remote sensing images on June 3, 2020 shows that the water body area of ​​the heritage site is about 220.79 hectares. The water area of ​​Jiuzhaigou core heritage site was finely extracted through high-precision UAV digital orthophoto. The interpretation of Jiuzhaigou's related sea water area has gradually expanded after 3 years of restoration and reconstruction, and the landscape has gradually recovered.

Jinghai restored to its former scenery (taken on June 4, 2020). Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

  Aiming at the rich natural landscape of Jiuzhaigou, the Fu Bihong team used 3D lidar scanning and drone aerial survey technology to collect all-round spatial information of important large-scale heritage scenes, perform high-resolution imaging of heritage scenes and collect heritage scene loads The texture information. At the same time, it integrates radar scan data and drone aerial survey images, carries out geometric modeling and texture image processing on heritage scenes, and initially completes the construction of high-precision digital models of key heritage sites.

Nuorilang Falls after the earthquake. Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

  Through scientific monitoring and evaluation, the research team has provided important scientific data and technical support for the scientific and orderly implementation of geological disaster management, vegetation ecology and water environment restoration and protection at heritage sites in the world natural heritage sites.

Rhino water body image comparison: just after the earthquake (August 10, 2017, left); nearly three years after the earthquake (June 9, 2020, right). Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

The royal blue rhino sea (photographed on June 10, 2020). Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

Three-dimensional high-precision modeling presents the landscape of Wuhuahai (left) and Jinghai (right). Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

High-precision three-dimensional aerial images show that the landscape of Shuzhenggou is gradually recovering. Photo courtesy of researcher Fu Bihong team of Institute of Aerospace Science, Chinese Academy of Sciences

  Fu Bihong said that the formation and evolution of many landforms in Jiuzhaigou World Natural Heritage Site are related to the dammed lakes and calcified deposits formed by the blockage of rivers such as landslides, collapses and mudslides caused by seismic activities. During the formation of the landscape, post-disaster restoration and reconstruction must adhere to the scientific concept of “mainly restoration of nature”. (Finish)