Chicago is dealing with a 40-foot diameter sinkhole that developed on its South Side. The hole opened up on April 18 and doubled in size in just a few hours. But what is a sinkhole, and how do they form? Experts say soil health plays a prominent role.
Medill Reports Chicago looked into the likely causes for the city’s new sinkhole and found some variation. There are two types of sinkholes: those induced naturally and those formed through human activity. It appears the new sinkhole was caused from human action.
Naturally formed sinkholes occur when bedrock below the soil softens over time from exposure to acidic water. Sinkholes from human activity are usually caused when water mains break and surrounding soil is sucked into pipes and carried away, leaving voids.
When heavy loads – most likely from vehicles – are placed on top of weakened soil, it collapses along with the structures it’s supporting.