Napa Valley quake. The biggest earthquake in 25 years struck California’s Napa Valley in the early hours of 24 August 2014. By processing two Sentinel-1A images, which were acquired on 7 August and 31 August 2014 over this wine-producing region, an interferogram was generated. The two round shapes around Napa valley, which are visible in the central part of the image show how the ground moved during the quake. Deformation on the ground causes phase changes in radar signals that appear as the rainbow-coloured patterns. Each colour cycle corresponds to a deformation of 28 mm deformation. The maximum deformation is more than 10 cm, and an area of about 30x30 km was affected significantly.