The European Space Agency (ESA) announced the results of a decision to use California’s Napa Valley earthquake as an opportunity to show how satellites might be able to provide information. In this case, the ESA tasked their low earth orbiting (LEO) Sentinel-1 satellite‘s Synthetic Aperture Radar Interferometry payload to take a look at the affected area. The payload helped to highlight the distortions in the Earth’s surface that resulted from the Earthquake, shown in the image above. It also pinpointed the earthquake’s origination area, identified by the bowed bands seen near the top center of the image.
The above image was created by using an image of the area that was taken by Sentinel-1 before the earthquake, and combining it with information collected by Sentinel-1 of the area after the earthquake. ESA call this an ‘interferogram.’ Why is this capability important? Because the satellite’s interferogram helps to show earthquake breaks that weren’t identified before, giving earthquake scientists a more complete earthquake map. In Napa Valley’s instance, the fault actually is shown to extend further than originally mapped.
How else might this help? Since I am not any sort of scientist, I can only give guesses. One might be to help identify unstable areas that have been created by an earthquake. Day after day interferograms showing daily changes in an area might be a way to determine that. This would give critical information to emergency responders about areas to avoid during and after a disaster. Another application might be for insurance agencies that may have a collection of annual images to show areas where soil shifts, helping to identify which areas would not be a great place to build a home.
Sentinel-1 is the first satellite of a two-satellite constellation. Sentinel-2 will launch sometime in 2015. There are five other ‘Sentinel’ satellites planned to orbit the Earth, but the ESA is putting a few of them in different orbits. Plans do change though…