California is notorious for its earthquakes, but a stunning new discovery reveals for the first time just how much we've underestimated its omnipresent earth-shaking potential. By the time you just about finish reading this story, in fact, Southern California will probably have experienced another quake - based off a new, unprecedented deep dive into 10 years' worth of seismic data, which isolated almost 2 million 'hidden' tremors in the region that scientists had never identified before. For decades, scientists suspected these invisible, smaller quakes existed, but had no way of singling them out from other random vibrations created by things like vehicle traffic, construction projects, weather events, and more. "It's not that we didn't know these small earthquakes were occurring," says geophysicist Zachary Ross from Caltech. "The problem is that they can be very difficult to spot amid all of the noise." Awareness of the prevalence of these quieter quakes in California dates back to