In earthquake-prone California, where geologists say that the "Big One" is virtually certain to strike before 2040, a few seconds of warning could save lives. Allowing more time to duck and cover is one of the major goals of the new Quake-Catcher Network (QCN), an affordable, citizen-based earthquake-detection system that turns idle laptop computers into seismic sensors.
Like other distributed-computing projects (such as SETI@home, which analyzes telescope data for signs of extraterrestrial life), QCN recruits volunteers to download software that harnesses the processing power of their computers and uses it to perform scientific tasks. But what's different about QCN is that it wields sensors as well as software.
Those sensors are small accelerometer chips built into every Apple laptop manufactured since 2004, as well as into post-2003 IBM Thinkpads and some recent HP and Acer models. The main purpose of such a chip is to prevent you from destroying precious data; if you drop your computer, the accelerometer detects the sudden movement and puts the brakes on your spinning hard drive. But it can also be used to detect ground rumblings.
When active, the computer's central processor samples the accelerometer 50 times per second, looking for any shaking that was not detected in the previous minute. If the computer detects a tremor, it sends a "trigger" message—containing information including the time and amplitude of the shaking—to a central computer. "It's looking for large numbers of triggers coming in all at once," Lawrence says. That's the signature of an earthquake, and a cue for the computers to relay detailed data about the event.
Users can register their five favorite locations so that their laptops will know where they are when the shaking is detected. Even if the user isn't at one of those locations, Lawrence says that in urban areas, "we can figure out where you are within about a mile" based on the IP address used to transmit the data. The network has already detected a magnitude-5.1 quake just west of Reno, Nevada. It's especially suited to areas too vast or budget-strapped to deploy more sophisticated sensors, which often cover too little ground to get an accurate reading and tend to go off scale during heavy shaking.
While QCN can only detect a quake after it starts, that may still provide enough time to prepare for the stronger shaking that follows. Digital data travels faster than seismic waves, so even though it might take several seconds for the QCN headquarters to register the first wave, that would still allow enough time to slow down a train or close a gas valve before the secondary wave strikes. In fact, experts estimate that just a five-second warning can reduce the death toll of a major quake, such as the one that killed at least 69,000 people in China last May, by as much as 80 percent.
But first QCN creators must work out the thorny details of how to issue warnings without stepping on any official toes or causing mass panic. And they have to recruit foot soldiers. So far, only a few hundred people have volunteered for QCN. But the more computers that are part of the network, the faster it works. "To do early warning, we'd want at least 1,000 [volunteers] for the Bay Area," Lawrence says. As it grows, the network might include iPhones and Wii remotes, which are also equipped with accelerometers. Ready to enlist? Visit qcn.ucr.edu.
Using accelerometers in devices to predict quakes is the start of a good idea. The next logical step is to convert confirmed quake data into immediate and automatic safe mode responses in trains, highrise elevators, and gas and water valves to eliminate the weak link in the response chain, the human time lapse in response to earthquake alarm data that is effective in savings the most lives only when the corresponding safe-mode response is immediate.
Yes, I know of this work and have followed it closely for at least 2-3 years. The seismology community is pushing hard for such an "Early Warning System".
However, the name is a blatant misnomer. It works by the same principle as one could imagine to use for dodging a bullet: When the gun fires, you see a flash of light. Knowing that light travels at about 300,000 km/sec, but the bullet travels toward you at "only" supersonic 2-3 km/sec, you are supposed to have time to run for cover.
The seismologists' latest "Early Warning System" works by trying to capture the P wave, after an earthquake has "fired", and to use it to calculate the arrival time of the destructive and potentially deadly S waves. P waves travel at about 6 km/sec, while the S waves travel at around 3.4 km/sec. If you are 12 km from the hypocenter, the time differential is 1.5 sec - barely enough to blink the eyes. If you are 120 km from the hypo- or epicenter, the time differential is about 15 sec. Some of this time, a few seconds using a supercomputer, goes into calculating that this is really a big earthquake and where it occurred. This leaves you with 10 sec at best to run for your life.
Bucharest in Romania has a working system in operation, I understand, and there it makes (almost) sense. Bucharest is located about 140 km from a unique, well-defined earthquake source region, the Vrancea Zone, just 70 km wide, where magnitude 7 type earthquakes occur rather frequently at a depth of 80-90 km. This gives Bucharest around 20 sec time to calculate the event and issue an "early warning". Practically this translates into 12-15 sec in useful time. Enough to take action with technical installations, trains, power plants etc. but not really enough to allow "normal" people to react.
What is most alarming is that the seismology community pushing for this "Early Warning System" in California is asking the local, state and federal governments to cough up hundreds of millions of dollars needed to install the necessary network of seismometers, of computing power and communication networks. At the same time they (as a group) refuse to even consider the work that a few of us "outsiders" are doing to understand the physics that underlies signals, which the Earth sends out weeks, days, hours before (most) major seismic events, worth $50K of funding.
Cheerful as ever,