Express.co.uk: Yellowstone volcano: How USGS tracks ground DEFORMATION with mill
imetre precision.
[1]https://www.express.co.uk/news/science/1123368/Yellowstone-volcano-USGS-groun
d-deformation-supervolcano-Yellowstone-news

References

   1. https://www.express.co.uk/news/science/1123368/Yellowstone-volcano-USGS-ground-deformation-supervolcano-Yellowstone-news