The effects of the magnitude-9 earthquake that hit All Japan news two years ago, on March 11, 2011, were so big that were even felt in space. According to scientists, the quake sent a ripple of sound through the atmosphere that was recorded by the Goce satellite.
The super-sensitive instrument managed to detect the disturbance as it passed through the thin wisps of air still present 255 km above the Earth, the international press reports. During major earthquakes, very low-frequency acoustic waves, or infrasound are generated. The infrasounds cannot be detected by the human ear.
So far, no spacecraft in orbit has been able to record the low-frequency acoustic waves.
“We have looked for this signal before with other satellites and have not seen it, and I think that is because you need an incredibly fine instrument,” said Rune Floberghagen from the European Space Agency (ESA).
“Goce’s accelerometers are about a hundred times more sensitive than any previous instrumentation and we detected the acoustic wave not onc, but twice – passing through it over the Pacific and over Europe,” the mission manager said.
The ESA spacecraft encountered the signal as it passed over the Pacific some 30 minutes after the onset of the quake, and then again 25 minutes later as it moved across Europe.