The earthquake off the coast of Sumatra in December 2004 triggered a massive tsunami affecting several countries around the Indian Ocean. The most significantly impacted were Indonesia, Thailand, Sri Lanka, India, and the Maldives. The first and second images, captured by the Envisat satellite over the Sri Lankan and Indian coasts, were acquired before and after the earthquake/tsunami event, on December 22 and December 28, 2004, respectively. The third composite radar image merges two images from the Envisat satellite acquired on April 28, 2004, and December 29, 2004, depicting the eastern part of Sri Lanka. The fourth composite radar image merges images from August 14, 2004, and January 1, 2005, illustrating the northern part of Sri Lanka.

• Image 1: Product: Satellite: Envisat, Instrument: Medium Resolution Imaging Spectrometre (MERIS), Acquisition Date: 22 December 2004, Orbit number: 14702
• Image 2: Product: Satellite: Envisat, Instrument: Medium Resolution Imaging Spectrometre (MERIS), Acquisition Date: 28 December 2004, Orbit number: 14788
• Image 3: Product: Satellite: Envisat, Instrument: Advanced Synthetic Aperture Radar (ASAR), Acquisition Date: 28 April 2004 - 29 December 2004, Orbit numbers: 11295 – 14802
• Image 4: Product: Satellite: Envisat, Instrument: Advanced Synthetic Aperture Radar (ASAR), Acquisition Date: 14 August 2004 - 01 January 2005, Orbit numbers: 12841 - 14845