Here is a PDF of a series of aerial photos taken during the 2016 Speed Week of the entire salt playa, not just the international speedway. The images show not only how much the circumference has shrunk, but the lack of solid white color reveals the thinning of the surface crust. Save the Salt is grateful to Dr. Bowen for sharing these images.

This is a VERY large compilation of satellite photos from the US Geological Survey. Note the location of the international race track, hot rod racetrack, circular endurance courses, various brine test wells, and even a landing strip! Note the dark line depicting the Salduro Loop dyke in the lower left corner is not yet salted up to provide a false "healthy thick salt" view from the Interstate 80 rest stop.