Another day, another major earthquake — this time, a magnitude 6.9 tremblor that killed at least 300 people in China’s Qinghai province. I’ve been talking to a lot of seismologists lately, and they all agree that the recent cluster of devastating earthquakes, including the jolt that shook northern Mexico earlier this month, do not point to some planet-wide upheaval; it’s all a statistical coincidence, they say. Well, that may be true, but it sure doesn’t feel that way. It feels like something is up. Not surprising, then, that a few days ago false rumors started proliferating in Southern California that the Big One would strike imminently.
Seismologists’ reassurances would be more soothing if they had a detailed, empirically verified understanding of how earthquakes work. Unfortunately, they’re the result of forces at work deep within the earth that are difficult to gather data on. So the science remains in its early stages. But progress is being made — and soon, you can be a part of the process. As I wrote recently on the Pop Mech website:
As part of their battle to understand and protect against the destructive force of earthquakes, seismologists have gone to extraordinary lengths. They have bored holes deep into the earth’s crust, laid out arrays of sensors hundreds of miles across, and built supercomputers capable of running simulations at teraflop speeds. But the most exciting new effort in cutting-edge seismology involves a piece of instrumentation that’s a good deal less exotic. It’s called an iPhone.
Here’s the rest of the piece:
“Each smartphone has an accelerometer built into it,” says Robert W. Clayton, a professor of geology at Caltech. “It’s primary function is to determine the orientation of the phone and to allow gaming. But it can also be used to detect seismic activity.” What’s more, the phone’s internet connection allows it instant access to remote servers. In essence, though consumers think of them that way, iPhones have the capability to serve as nodes in a distributed seismic sensor network. All they need is someone to organize that network. Clayton is part of a team aiming to do just that. Called Community Seismic Network, the project will debut this summer with a tight cluster of sensors in the Pasadena area.
Volunteers are being issued inexpensive three-axis accelerometers, each about the size of a stopwatch, that can plug into any computer’s USB port. Later, the network will expand to include laptops equipped with built-in accelerometers and then to smartphones. The project is running in parallel with a Stanford-based effort called the Quake Catcher Network that is already collecting data from volunteers around the world.
When a sensor detects a vibration that could be an earthquake, it automatically sends a report over the Internet. “The goal is to pass on the key information within a second, so it beats the destruction of the earthquake,” Clayton says. “We call it the Temple of Doom scenario,” after the scene where Indiana Jones runs out of the imploding temple just before it collapses around him. The plan is to have 1000 to 2000 sensors in the network within a year, and eventually as many as 100,000 spread out across the greater Los Angeles area.
When completed, the network will include both stationary computers and mobile devices, providing block-by-block level of detail. Mobile devices have one huge drawback when it comes to sensing earthquakes: they’re subject to all sorts of extraneous vibration and movement as their users navigate around a noisy world. The key will be to develop software that can discriminate between the kinds of signals generated by temblors from everything else. Helping the cause will be the fact that, since each iPhone is part of a much wider network, false positives will be easy to spot against an otherwise quiet background.
Ultimately, Clayton says, “I’m hoping that we’ll be able to detect earthquakes as small as magnitude 3.0.” The information could feed into an earthquake early-warning system, to alert the population that a temblor is on the way. Since the signal travels at almost the speed of light, and the quake propagates at the speed of sound, those living at the edges of an affected area could have up to a minute’s warning. “That’s not enough time to evacuate an area,” says Caltech researcher Egill Hauksson, “but it could give a surgeon enough warning to stop cutting, or for a teacher to get her students under their desks.”
The Community Seismic Network could also help provide seismologists with unprecedentedly detailed knowledge of how the earth shifts during a quake. That, in turn, could help them arrive at such a thorough understanding of seismic forces that they will be able to predict massive earthquakes before they strike. And that, says Hauksson, is “the holy grail of seismology.”