It’s not unknown that some major urban areas in the United States are sinking. Small measurements, big impactsWhile land sinking less than an inch per year might not seem like much on paper, small shifts in land can have big effects. This new study used satellite-based radar measurements to create high-res maps of subsidence–or sinking land– in these areas. “Several telltale signs of land subsidence are visible to the naked eye and may indicate early stages of ground sinking or differential settlement,” he says. Based on the data from this study, the team suggests that cities integrate land subsidence monitoring into urban planning policies to keep risks from getting worse.