March 11, 2013
Space Seismometer Recorded Japan’s 2011 Earthquake, Two Years Ago Today
WATCH VIDEO: [Earthquake Sensed By GOCE]
Lee Rannals for redOrbit.com — Your Universe OnlineTwo years ago today, Japan was rocked by a 9.0-magnitude earthquake and giant tsunami that caused both death and destruction throughout the country. Now, with instrument's like the European Space Agency's (ESA) GOCE satellite, scientists will be able to understand a bit more about these devastating quakes and how they rock Earth.
ESA launched the hyper-sensitive GOCE gravity satellite in 2009, becoming the first space agency to put a seismometer in orbit. Before GOCE, satellites were never able to see sound waves from an earthquake in space. Earthquakes cause the surface of the planet to vibrate like a drum, producing sound waves that can be seen through the atmosphere.
Only low-frequency, infrasound is able to reach the atmosphere, causing vertical movements that expand and contract the atmosphere by accelerating air particles. With the GOCE satellite, scientists are able to see how the March 11, 2011 Japan quake was felt in the atmosphere as well.
GOCE orbits the Earth at the lowest altitude of any observation satellite, sitting at just 167 miles above the surface of Earth. Due to its low orbit, it has to cope with air drag as it cuts through the remnants of the atmosphere. The satellite carries an ion engine that instantly compensates for any drag by carefully calculating thrusts.
Measurements taken by GOCE helps ensure the satellite remains ultra-stable in its low orbit to collect very precise measurements of Earth's gravity, atmospheric density and vertical winds.
GOCE was able to detect sound waves from the massive earthquake, and ESA released a video (link at top of article) to demonstrate how it affected the Earth's atmosphere. When GOCE passed through the sound waves from the quake, its accelerometers sensed the vertical displacements of the surrounding atmosphere similar to seismometers on the surface of Earth.
“Seismologists are particularly excited by this discovery because they were virtually the only Earth scientists without a space-based instrument directly comparable to those deployed on the ground," Raphael Garcia, from the Research Institute in Astrophysics and Planetology, said in a statement. “With this new tool they can start to look up into space to understand what is going on under their feet.”
Japan's 2011 earthquake was tied for the fourth-strongest earthquake since 1900, and the ensuing tsunami is said to have been the highest ever recorded in Japan.The two disasters resulted in over 15,000 fatalities, with thousands more missing.
Experts from the Woods Hole Oceanographic Institution (WHOI) issued a statement a few days after the devastating event, urging scientists to dive-in and use the earthquake as a chance to learn about future quakes around the world. Since then, numerous studies have been released centering around the powerful earthquake, including one in July 2011 about how the massive tremor affected the rocks and soil beneath the surface.
With instrument's like GOCE, and scientists capitalizing on large seismic events like the 2011 Japanese temblor/tsunami combo, we are sure to gain a better understanding for how these events could potentially shape our future planet.