• NASA has crunched the data from satellite images to show the true extent of the damage to Beirut after an explosion rocked the city last week.
  • By comparing before and after images, the system can detect where the most serious damage occurred.
  • Maps like this help emergency responders direct resources to areas where survivors may still be waiting to be rescued.

Last week a devastating explosion rocked the city of Beirut. It happened near the Port of Beirut, and there are many eyewitness accounts and videos showing the intense blast as well as the aftermath from the ground. It was a tragedy that claimed well over 100 lives and injured countless others, and the cleanup and repairs will undoubtedly take years to complete.

NASA’s Earth-gazing satellites are often used to spot changes in large areas, like melting icebergs or the effects of wildfires. Now, in partnership with the Earth Observatory of Singapore, NASA has used data from these high-flying observation tools to produce a map that shows just how widespread the destruction in Beirut is.

By comparing previous satellite images of the same region with new images taken after the explosion, NASA’s systems can detect both large and small changes in the landscape. This includes things like collapsed buildings and changes to the geography of the area. The system labels each spot where it notices a difference, and the darker the pixel, the more dramatic the damage is.

“NASA’s Advanced Rapid Imaging and Analysis (ARIA) team, in collaboration with the Earth Observatory of Singapore, used satellite-derived synthetic aperture radar data to map the likely extent of damage from a massive Aug. 4 explosion in Beirut,” NASA explains in a new blog post. “Synthetic aperture radar data from space shows ground surface changes from before and after a major event like an earthquake. In this case, it is being used to show the devastating result of an explosion.”

When maps like this are generated, it’s not just for the purposes of seeing how bad things are. The levels of devastation in any given area can be a big indicator for emergency personnel that wants to try to find survivors among the wreckage. When damage is this widespread, it’s sometimes not immediately clear where emergency responders should focus their attention, but these maps act as a guide to push them in the right direction.

The explosion reportedly occurred when a massive stockpile of ammonium nitrate caught fire. The 2,750 tons of the chemical had been stored in a warehouse near the port for roughly six years. In agriculture, it’s often used as a fertilizer, but it’s also highly explosive under the right conditions. While reports of casualties are ever-changing, the explosion may have killed as many as 220 people, with at least another 100 people still missing from the surrounding area.

Mike Wehner has reported on technology and video games for the past decade, covering breaking news and trends in VR, wearables, smartphones, and future tech. Most recently, Mike served as Tech Editor at The Daily Dot, and has been featured in USA Today, Time.com, and countless other web and print outlets. His love of reporting is second only to his gaming addiction.