Humans are an unknown in California's new earthquake warning system

When a big earthquake struck Mexico City in September 2017, Allen Husker, a seismologist at the National Autonomous University of Mexico, ducked under his desk. The nearby temblor hit before the school's early warning alarm bells could even start blaring. But almost everyone else ran outside. 

"I was one of the only people left in my office," Husker said. "There was a panic," he added, noting that it's dicey to race down stairs when the world is violently shaking. 

The event illustrates the short-lived chaos that can ensue during temblors and the way different people — sometimes with vastly different understandings about earthquakes — react to the same shaking.  Read more...