Emergency services are already preparing for how to deal with a terrible off-shore earthquake in the Cascadia Subduction Zone, off the west coast of America near California. They were just completing their four-day major emergency test run when a 5.2 magnitude quake hit Borrego Springs, San Diego County, in California on Friday.

The mid-sized earthquake caused more than 200 aftershocks – some more than three on the richter scale – and could be felt from Santa Barbara to the Mexican border. Egill Hauksson, a research professor of geophysics at Caltech, said of the 5.2 quake: “It was the biggest one for a while.” CONTINUE