The shaking woke Thomas Heaton on a quiet winter morning in Pasadena, California. The streets were empty, with sunrise hours away. As Heaton lay in bed next to his wife, waves vibrated through their house. Ten seconds. Fifteen. Twenty. As a seismologist, Heaton had spent his career studying seismic waves like these. By feel and duration, he guessed this quake was big, maybe a magnitude 6.5, and close, under west Los Angeles. Plenty dangerous. An aftershock rolled through. He was needed. “I’ve got to get to work,” he told his wife.
At the time, in 1994, Heaton was the lead scientist at the earthquake field office of the U.S. Geological Survey (USGS) in Pasadena. He drove to the office in darkness, imagining the fires, collapsed bridges, and crumbled buildings closer to the epicenter. At the office, seismic readings partially validated his gut: “I was right about the magnitude and approximate distance,” he says—though not the location. The quake had struck farther north, under the neighborhood of Reseda, on a previously unknown fault. The Northridge quake, as it came to be known, killed 57 and caused many billions of dollars in damage. There had been no warning, no sirens sending people into the streets. Heaton recalled how he had guessed the size of the earthquake when the first, gentle waves reached his bedroom. There must be a way, he thought, to translate his gut check into a short but useful warning.
After decades of work, Heaton’s dreams have taken form. Last month, USGS unveiled ShakeAlert, the West Coast’s earthquake early warning system. If all goes as planned, a dense network of seismometers in California, Oregon, and Washington will detect the first, weak waves of an earthquake and relay a rapid warning of ground shaking to come. To start, those warnings will go to first responders, power companies, and transit agencies. But in the next couple of years, alerts could roll out to the public to provide at least a few seconds of warning. Not much time, but enough to “drop, cover, and hold on,” says Doug Given, a geophysicist in Pasadena who is leading the USGS effort.