The New Yorker:

From 2021: The newest warning systems give users ten seconds’ notice. What can be done in that time?

By Zoey Poll

One Saturday afternoon a few years ago, Richard Allen was riding Bay Area Rapid Transit between Berkeley and Oakland when the train suddenly stopped. “We’ve had an alert for an earthquake,” the conductor announced. “We’re going to assess the situation and decide what to do.” Allen, the director of the Seismological Laboratory at the University of California, Berkeley, had spent much of the previous two decades working toward that moment. He studied the faces around him, looking for signs of panic. A couple of locals sat down and inspected their phones; a family of tourists joked about their Bay Area bucket list (Alcatraz, Golden Gate, earthquake—check). After a few minutes’ orderly wait, the train’s journey resumed. Apparently, earthquake early warning, or E.E.W.—the technology that Allen had been championing since 2001—could feel routine, like an everyday inconvenience.

In fact, the warning on the train was quite novel. Allen’s fellow bart riders likely didn’t know that their train could brake in anticipation of shaking, not because of it. Using data derived from every major Californian quake since the late nineteen-eighties, the system had provided the riders with a brief warning of the onrushing quake. It will cost more than sixty million dollars to complete, with an annual maintenance cost of thirty million. Still, Allen and others believe that it can prevent at least half of all injuries in the next major earthquake, while possibly avoiding millions of dollars in damages.

Earthquake early warning is not earthquake prediction. The last time the United States Geological Survey tried to predict a seismic event was in 1984, and the shaking arrived at the prophesied epicenter, in Parkfield, California, eleven years too late. In a 2009 book, “Predicting the Unpredictable: The Tumultuous Science of Earthquake Prediction,” the geophysicist Susan Hough explains that earthquakes seem to “pop off in the crust like popcorn kernels”; seismologists may have “no way to tell which of the many small earthquakes will grow into the occasional big earthquake.” As a result, researchers have essentially given up on the idea of pinpointing when a quake will occur.

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