Just before the shaking began, everyone’s phones began buzzing. Schoolchildren, railway drivers, dentists and firefighters all looked down at their phone just before 2:46pm local time on a spring Friday on the Oshika Peninsula of Tohoku, in Japan. Earthquake, it told them. And then, eight seconds later, the shockwaves of a 9.0-magnitude earthquake hit them. More than 10,000 people were killed by the shaking and the resulting tsunami that struck the nation’s east coast on March 11, 2011. But perhaps millions of lives were saved, experts later declared, by what is now the world’s most sophisticated national earthquake warning system.
Earthquakes are very hard to get in front of. The trouble with trying to predict the shaking of the ground based on history is that in geological terms, humans have only been around for a fraction of a second. We simply haven’t seen enough of the history of the earth’s movements to know what the future looks like. “We’ve been watching earthquakes seriously for about 50 years,” says Thomas Heaton, director of the CalTech Earthquake Engineering Research Laboratory. “To think that in the last 50 years of recording we’ve captured the important parts? Well, probably not. So there’s probably a lot of surprises still out there for us.”
How does Japan get an eight-second jump on the surprise? The national system there is a network of 1,000 seismographs that detects the first P-waves of an earthquake. P-waves are long-frequency movements of the earth that arrive first, and generally don’t do much damage. It’s the S-waves — short, staccato bursts of energy that arrive later and shake buildings to pieces — that the warning system is designed to anticipate.
“Even with a couple of seconds there’s a lot you can do,” says Lucile Jones, science advisor for risk reduction at the US Geological Survey. “The dentist can take the drill out of your mouth, the surgeon takes the knife out of your chest. Theres also a lot of automatic things that can be done in manufacturing settings.”
At the moment, the United States has only a small test network of seismographs in operation in California. The system, called ShakeAlert, sends warnings to a small group of project participants. There has been little or no interest in the problem from Silicon Valley, which sits astride one of the most historically active fault systems in the world, but hasn’t found a business model in detecting events that occur at million-year intervals. And so earthquake detection in the United States — even in places that stand to lose the most — has largely stalled.
Finding the funding for even a general warning system for the Pacific States would cost tens of millions of dollars. For a system covering the entire nation, it might take billions. Japan has the distinction of being a country that’s seismically active all over the nation, such that lawmakers there have directly experienced earthquakes. Few lawmakers in the United States have ever directly experienced the damage a big shake can do.
And that’s the trouble with humans, who live a century at most, making decisions about a threat that can strike at any time over millions of years. In the years 1811 and 1812, according to comparisons of various accounts written at the time, at least two earthquakes of magnitude 7 or higher — enormous, deeply dangerous events —shook Southern Missouri, a state no one associates with earthquake damage. An event like that might shift national priorities enough to fund a nationwide warning system.
“If you took those earthquakes and moved them to the United States today,” says Heaton. “Well, basically people would have a very different opinion about earthquakes.”