Researchers at the University of California, Berkeley, have unveiled a free Android app that harnesses a smartphone's ability to detect whether its movement is likely caused by an earthquake or by human activities.
The MyShake app, launched on Friday, then transmits the data to a processing centre where it can be used, along with the information from millions of other smartphones, to potentially warn users of imminent tremors from nearby quakes.
"The accelerometers in the smartphones are actually similar to the ones used in seismology," said Qingkai Kong, lead researcher at the Seismological Lab at University of California, Berkeley.
"Even though they are relatively low quality, we thought there's a potential to use them to detect earthquakes."
The app runs in the background and consumes only a small amount of power.
"Low power consumption is important and we tried to make the impact on the users as small as possible," said Qingkai.
Not a prediction system
The app has the potential to warn of impending tremors, but Roger Musson, a seismologist with the British Geology Survey, said it is only of practical use when the community at risk is some distance from the earthquake.
"If the earthquake is 300km away, you might get a couple of minutes advance warning," he said.
"If you live close to an earthquake fault, the interval will be very short indeed, so the question is: what can you do with early warning amounting to some seconds?"
Qingkai says even a prediction of just a few seconds can be valuable, especially when strategic or sensitive facilities are programmed to automatically shut down when a tremor is detected.
"It can be used for slowing down high speed trains to stop them being derailed, shutting down nuclear reactors, protecting sensitive machinery in factories or even stopping flights from landing during the shaking," Qingkai said
Warning systems already exist, such as one operated in Japan to stop the Shinkansen high-speed train when a large quake occurs.
If widely adopted, MyShake would have the advantage of having many times more sensors than traditional systems, and have them much more densely placed.
"The best traditional seismic network is about 10km between nearest stations, but for the smartphones we will have the sensors basically on each block in the cities, a very dense network," Qingkai said.
"This dense network can contribute to the existing traditional seismic network to make faster and more accurate earthquake detection."
The researchers admit the system does have limitations, including the fact the accelerometers in smartphones are relative poor quality.
Also, the ability to accurately detect earthquakes relies on the app being installed in a large number of phones, all in close proximity to each other.
The team say it is likely to more effective at certain times of the day.
"It works best during the night, since the majority of phones will be placed on the desk or not moving, but during the day we lose some of the sensors, since they will be moving around," Qingkai said.
There are also concerns the system, which relies on real-time data processing and advanced algorithms, may generate false alarms.
"The algorithms to estimate an earthquake's size from the initial wave characteristics are complicated and difficult to calibrate," Martin Mai, a professor of earth science and engineering at King Abdullah University, told Al Jazeera.
"False alarms are a problem."
The researchers say getting the algorithm right has been a major challenge.
Beyond its technical and scientific aspects, Mai says the success of the app depends on how people respond to an alert.
"Imagine if a whole city receives this message and jumps into action within seconds, and shuts down systems,and then the shaking is low," he said.
"Everyone is relieved and continues their business.
"If this happens a few times, then will people [continue] to react and be prepared as they were the first time?"