Precursor: Japan Quake May Have Struck Atmosphere First
October 12, 2011 • 9:49AM

"Before finding this phenomenon, I did not think earthquakes could be predicted at all," Hokkaido University geophysicist Kosuke Heki told OurAmazingPlanet. "Now I think large earthquakes are predictable."

The phenomenon to which Heki referred, is that the devastating earthquake that struck Japan on March 11 this year may have rattled the highest layer of the atmosphere even before it shook the Earth. The discovery could one day be used to provide warnings of giant quakes.

The magnitude 9.0 quake that struck off the coast of Tohoku in Japan ushered in what might be the world's first complex megadisaster, as it unleashed a catastrophic tsunami and set off microquakes and tremors around the globe. Scientists recently found that the surface motions and tsunamis this earthquake generated, also triggered waves in the upper atmosphere. These waves reached all the way to the ionosphere, one of the highest layers of the Earth's atmosphere.

But now Professor Heki reports that the Tohoku quake also may have generated ripples in the ionosphere before the quake struck. Disruptions of the electrically charged particles in the ionosphere lead to anomalies in radio signals between global positioning system satellites and ground receivers, data that scientists can measure. Heki analyzed data from more than 1,000 GPS receivers in Japan. He discovered a rise of approximately 8% in the total electron content in the ionosphere above the area hit by the earthquake — about 40 minutes before the temblor. This increase was greatest about the epicenter, and diminished with distance away from it.

Professor Heki concluded that this means earthquakes may be forecast, if nations are able to monitor changes in the ionosphere near earthquake regions in real time.