Satellite detected Japan's 2011 earthquake and tsunami

Last March 11 the world remembered the earthquake and tsunami that hit Japan on 11 March 2011. New studies have revealed that this massive quake was also felt in space by ESA's satellite GOCE (Gravity field and steady-state Ocean Circulation Explorer).

GOCE was launched in 2009 with the main objective of mapping Earth's gravity, the fundamental force that pulls mass. In order to achieve its very challenging mission objectives, this slender, five-metre long satellite is designed to orbit at a very low altitude of just 260 km because the gravitational variations are stronger closer to Earth.

The following video provides more information about GOCE and gravity.

Earthquakes not only create seismic waves that travel through Earth’s interior, but large quakes also cause the surface of the planet to vibrate like a drum. This produces sound waves that travel upwards through the atmosphere.

Scientists from the Research Institute in Astrophysics and Planetology in France, the French space agency CNES, the Institute of Earth Physics of Paris and Delft University of Technology in the Netherlands, supported by ESA’s Earth Observation Support to Science Element, have discovered that GOCE detected sound waves from the massive earthquake that hit Japan on 11 March 2011. When GOCE passed through these waves, its accelerometers sensed the vertical displacements of the surrounding atmosphere in a way similar to seismometers on the surface of Earth. Wave-like variations in air density were also observed.

GOCE opens a door that will allow to understand our planet by looking up to the space.

The following animation shows how the massive earthquake that hit Japan in 2011 caused ripples in the atmosphere. As sound waves from the earthquake travelled upwards, they caused changes in air density that were detected by ESA’s GOCE gravity satellite as it crossed the wavefront.

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Additional reading:
GOCE: The first seismometer in orbir OCE/GOCE_the_first_seismometer_in_orbit
GOCE feels quake
GOCE