Though not the first time that Mexico City's sinking has been observed from space, the Nisar mission has provided a greater sense of how far the sinking spreads and how it changes across different types of land than any other space-based sensor. It has also been able to penetrate areas on the outskirts of the city that were previously challenging to study because of the complex terrain. The implications of the imagery extend far beyond the Mexican capital. "This study of Mexico City speaks to the realm of possibilities that will open up thanks to the Nisar system," said Dario Solano-Rojas, an engineer at the National Autonomous University of Mexico (Unam). "And not just for sinking cities but also for studying volcanoes, for studying the deformation associated with earthquakes, for studying landslides." According to Nasa, the technology is also capable of monitoring the climate crisis, glacier sliding, agricultural productivity, soil moisture, forestry, coastal flooding and more. The Nisar system found that some parts of the city are dropping by more than 2cm a month. "First documented in 1925, the city's sinking is a result of centuries of exploitation of the groundwater," the report says. "Because Mexico City and its surrounds were built on an ancient lake bed, the soil beneath the city is extremely soft. When water is pumped out of the aquifer below, this clay-like earth compacts, resulting in a city that is quietly sinking."
The crisis is also self-reinforcing: as the city sinks, aging pipes crack and leak, causing Mexico City to lose an estimated 40% of its water, even as drought and climate change make supplies more fragile.
Read more of this story at Slashdot.


