East Africa: Remote Sensing satellites help monitor tectonic plates

Tiny changes on the ground changes the radar signal
Surface displacements in Malawi
Credits: ESA

The use of remote sensing techniques such as the Interferometric Synthetic Aperture Radar (InSAR) are helping scientists to better understand plate tectonics by providing patterns and consequences of activity that can help to get a clearer picture of a volcano’s behavior. For example, by using InSAR, scientists can monitor the moving apart of the two tectonic plates in the East African Rift by detecting surface displacement with centimetre accuracy. In doing so, data from ESA's Envisat satellite revealed that the dormant Mount Longonot in Kenya rose by 9 cm from 2004-2009.

InSAR is a remote sensing technique in which two or more radar images over the same area are studied in combination in order to perceive and detect slight changes in the surface. When the land is uplifting or subsiding, even by tiny changes on the ground, the radar signal changes showing rainbow-coloured interference patterns in the combined image, which is called a SAR interferogram.