Warning

The FDA is cracking down on a number of companies selling cannabidiol (CBD) products accompanied by unsubstantiated health claims. The latest target is a company called Curaleaf, which sells CBD products claimed to treat everything from cancer and Alzheimer’s, to anxiety and inflammation in dogs.

While current seismometers can pick up tremors with precision, they’re short-ranged and expensive. Now a Stanford study has demonstrated that an extensive earthquake-detection network could already exist right under our feet: the optical fiber cables piping high-speed internet throughout cities.