EPSS Colloquium winter-2022

Interferometric measurements from orbiting radar, which 30 years ago so dramatically revealed ground movements associated with the Landers earthquake, has evolved into a routine ground engineering monitoring tool able to measure the subtle movements caused by tunnelling and dewatering. At up to 90 metres deep, London's Tideway Tunnel provided the perfect opportunity to test the limits of the technique. The results proved stunningly far from mundane, identifying ongoing geological fault movements an order of magnitude smaller than ever previously measured, in a location where such movements were completely unexpected and yet entirely predictable. Moreover, they demonstrated that here was a tool capable of determining from orbit whether Venus is as active as Earth or as dead as Mars, a key measure in understanding why our 'twin' planet is so different to our own. The discoveries in London also reveal a new way of understanding the geology of our nearest neighbour that resolves the paradox of its impact crater distribution. This talk discusses how EnVision overcame technical challenges and overturned a geological paradigm to win the M5 selection.