By finding a close link between electrical disturbances on the edge of our atmosphere and impending quakes on the ground below, NASA scientists have said that they could be on the verge of a breakthrough in their efforts to forecast earthquakes.
Despite years of searching for earthquake precursors, there is currently no method to reliably predict the time of a future earthquake. Yet, most scientists agree that some form of early warning system could save tens of thousands of lives.
Now, according to a report in BBC News, NASA scientists teamed up with experts in the UK to investigate a possible space-based early warning system.
The ionosphere is distinguished from other layers of Earth's atmosphere because it is electrically charged through exposure to solar radiation.
On a significant number of occasions, satellites have picked up disturbances in this part of the atmosphere 100-600km above areas that have later been hit by earthquakes.
One of the most important of these is a fluctuation in the density of electrons and other electrically charged particles in the ionosphere.
Though full details have yet to be released, according to the BBC, scientists observed a "huge" signal in the ionosphere before the Magnitude 7.8 earthquake in China on 12 May.
The team at NASA has also been working with Surrey Satellite Technology Limited (SSTL) in the UK, to investigate the feasibility of a satellite-based early warning system.
Minoru Freund, a physicist and director for advanced aerospace materials and devices at NASA's Ames Research Center in California, believes other earthquake "precursors" could feed into this system.
These include enhanced emission of infrared (IR) radiation from the earthquake epicentre, as well as anomalies in low-frequency electric and magnetic field data.
Minoru and his father Friedemann Freund, also from NASA Ames Research Center, developed the scientific theory behind these earthquake precursors.
It boils down to the idea that when rocks are compressed - as when tectonic plates shift - they act like batteries, producing electric currents.
According to their theory, the charge carriers consist of a specific type of electron, called a phole, which can travel large distances in laboratory experiments.
When they travel to the surface of the Earth, the surface becomes positively charged. And this charge can be strong enough to affect the ionosphere, causing the disturbances documented by satellites.
"I do believe that we will be able to establish a clear correlation between certain earthquakes and certain pre-earthquake signals, in an unbiased way," said Freund.