Scientists report new evidence of Marsquakes

Scientists using photos taken by NASA's Mars Reconnaisance Orbiter say the surface of Mars appears to have experienced quakes only very recently. The suggestion raises possibility of existence of active volcanoes and reservoirs of liquid water on Mars.

According to Time, a team of British scientists using ultra-high-resolution images from the High Resolution Imaging Science Experiment (HiRISE), a camera carried by the Mars Reconnaissance Orbiter, found evidence of recent quake in a region of the planet known as Cerberus Fossae close to the Elysium Mons volcano. The research study, published in the March edition of the Journal of Geophysical Research, analysed the pattern of boulders that rolled off a cliff on the Cerberus Fossae region. Space.com reports the researchers found that the number and size of the boulders decreased over a 62 miles radius from a focal point along Mars' Cerberus Fossae faults. According to lead author Gerald Robert of the University of London: "This is consistent with the hypothesis that boulders had been mobilized by ground-shaking, and that the severity of the ground-shaking decreased away from the epicenters of marsquakes." Time reports that earlier images of the Cerberus Fossae region taken had shown that the region was the product of very recent lava flow with faults cutting across the lava fields suggesting a quake might have happened not long ago. The scientists decided to search for fallen boulders to confirm their suspicion. Roberts said: "On Earth, when an earthquake strikes, it often makes loose boulders roll, and the closer to the epicenter they are, the more they move." Using high resolution images, they began searching to see if they could find evidence of recently fallen boulders on Mars, and after examining several boulders, they found evidence that some of them had rolled off cliffs recently. Roberts said: "The boulders left tracks in the dust showing that they'd rolled or even bounced down slopes." The scientists pointed out that if the boulders had fallen after thawing of subsurface ice that bound them in place, the pattern of the falling would have been random. The researchers, according to Space.com, pointed out that the pattern resembled the pattern of boulder falls in a 2009 quake near L'Aquila in Italy. They also concluded that the quake must have occurred very recently because Martian winds have not yet erased the boulder tracks. New Scientist reports that because the lava fields the faults cross are just 2 million years old, scientists had thought the quakes may have occurred as recently as 2 million years ago. But with the knowledge that tracks from the Mars rovers are covered up within a few years, they think the displaced rocks could have been shaken up even more recently. The researchers said they believe quakes may still be ongoing on parts of the planet. If this is so, it could help scientists in the search for life on the planet because the heat of active volcanoes could melt some of the planet's subterranean ice and form bodies of water that may be conducive to the development of life. Roberts and his colleagues estimated the magnitude of the quake to be about 7. Space.com reports this is about the same magnitude as the 2010 Haitian quake that killed perhaps 300,000 people. The scientists speculate the quake may have resulted from movements of magma in the Elysium Mons Volcano nearby. Time reports the new evidence is important because scientists had for long believed that Mars is geologically dead having concluded that the inner heat of the planet must have been lost earlier in its history. The first signs that they might be wrong about this came with evidence of lava flows dated to as late as 2 million years, and sensors that detected methane, a gas produced in volcanic eruptions.