Mexico City is built on a unique ground containing the clay-rich sediments of the ancient lake Texcoco. Continuous imperceptible shaking of these deposits by city traffic and other sources allows us to monitor changes in the subsurface seismic wave speed. Wave speed varies seasonally, likely due to temperature and rain effects; it temporarily drops after large earthquakes then starts to recover. Throughout the studied period, it increased on average, which may be related to soil compaction.

Mexico City, a large megacity with over 21 million inhabitants, is exposed to several hazards, including land subsidence, earthquakes, and flooding. Our data makes it plausible for an earthquake triggering case that temporarily accelerated the subsidence rate in the metropolitan area as a result of the September 2017 earthquakes that affected Mexico City. Furthermore, the triggering effect induced rapid slip along previously developed shallow faults associated with subsidence.

Differential subsidence produces damage to infrastructure and geological media. However, detecting and mapping differential subsidence at a regional scale using satellite date becomes challenging when considering the large amount of displacement products that can be produced. Here we show some examples of our work with products at different scale and focused on different aspects of differential subsidence.