Mars: cause of the Red Planet's biggest quake revealed - and it's not what scientists first thought

The likely cause of the biggest-ever quake on Mars has been revealed by a UK-led study.

A global team of scientists suggest the 4.7 magnitude quake, recorded by Nasa's InSight lander was not the result of a meteorite hitting the planet, as after a search covering 144 million kilometres squared, the team found no fresh crater.

The quake was instead caused by enormous tectonic forces within Mars’ crust which caused vibrations to reverberate through the planet for at least six hours, on May 4 2022. However, the event, dubbed S1222a, was similar to previous quakes known to be caused by meteoroid impacts, and led to an international search for a fresh crater.

The teams used data from their satellites orbiting Mars to look for a new crater, or any other tell-tale signature of an impact, like a dust cloud appearing in the hours after the quake.

Although Mars is smaller than Earth, the two planets have similar land surface areas because Mars has no oceans. The results, published in the journal Geophysical Research Letters, indicate Mars is far more seismically active than scientists believed.

Study lead Dr Benjamin Fernando of the University of Oxford, worked with the European Space Agency, the Chinese National Space Agency, the Indian Space Research Organisation, and the United Arab Emirates Space Agency and this is thought to be the first time that all missions in orbit around Mars have collaborated on a single project.

Dr Fernando said: “We still think that Mars doesn’t have any active plate tectonics today, so this event was likely caused by the release of stress within Mars’ crust. These stresses are the result of billions of years of evolution; including the cooling and shrinking of different parts of the planet at different rates.

“We still do not fully understand why some parts of the planet seem to have higher stresses than others, but results like these help us to investigate further. One day, this information may help us to understand where it would be safe for humans to live on Mars and where you might want to avoid.”

He added: “This project represents a huge international effort to help solve the mystery of S1222a, and I am incredibly grateful to all the missions who contributed. I hope this project serves as a template for productive international collaborations in deep space.”