What's shaking on Mars? A new study suggests that tremors may have rattled the Red Planet just millions of years ago. These earthquakes, well, Marsquakes, could even be ongoing today. That would mean that Mars is not geologically dead, as is usually assumed.

A team of European scientists analyzed imagery of a Martian fault system from a NASA orbiter. In the high-resolution photos, the researchers could identify individual boulders that have tumbled down cliffs near the fault.

They found that the most rockfalls, and the biggest boulders, were concentrated around one part of the fault system. That’s what you would expect near the epicenter of a Marsquake. And it’s not what you would expect from a more mundane cause—avalanches caused by melting ice, for instance. The study appears in the Journal of Geophysical Research. [Gerald P. Roberts et al., "Possible evidence of paleomarsquakes from fallen boulder populations, Cerberus Fossae, Mars"]

Because the fault system cuts through terrain that is just millions of years old, the Marsquakes themselves would also have been very recent. Some rockfalls appear so young that winds have not yet erased the tracks left by boulders rolling downhill.

Whether the Red Planet remains geologically active is uncertain. But rolling rocks support the idea that Mars is still rocking and rolling.

—John Matson

[The above text is a transcript of this podcast.]