A Marsquake Deep Under Mars' Giant Canyon Shows the Planet Still Cracks

Mars' enormous canyon system is not just a frozen relic. A marsquake recorded by NASA's InSight lander came from a fault deep beneath Valles Marineris, and scientists say the finding shows the canyon is still tectonically active, billions of years after it formed, according to EarthSky.

The peer-reviewed study, by researchers at Columbia University and Imperial College London, was published in Nature Communications on Oct. 15, 2026. The teams discussed the result on Oct. 19.

How a single marsquake pointed to the canyon

InSight detected the quake, named S0976a, on Aug. 25, 2021, from its location in Elysium Planitia, on the opposite side of Mars from Valles Marineris. At first it was unclear whether the signal was a quake at all, because landslides and meteorite impacts can also make Mars tremble.

Researchers then found that the waves had traveled through Mars' core, and they traced the source to the western Valles Marineris region. Its exact location and cause remained unclear until the new analysis, which placed the quake 12 to 25 miles (20 to 40 km) beneath the canyon.

By studying the amplitudes and direction of the seismic waves, the team reconstructed what happened. Their conclusion is that the most likely cause was a strike-slip event, in which two blocks of crust slide sideways past each other along a steep fault with a deep root. EarthSky reports the quake was equivalent to a magnitude 5 quake on Earth.

Why Mars shakes without moving plates

Earth's quakes come from tectonic plates that push, pull and grind against one another until built-up stress snaps. Mars works differently. Scientists describe its crust as a single lid that has been slowly cooling. As the planet cools, the crust shrinks and cracks, creating faults. Some faults that formed billions of years ago can still slip.

Lead author Jung-Hun Song of Imperial College London said several different kinds of evidence agree. The seismic waves show a sideways slip on a fault well below the surface, while orbital images reveal a region crossed by long-lived fault systems. Song said this is not a “dead” fossil landscape, because faults beneath the canyon can still slip and generate marsquakes.

The canyon in numbers

Valles Marineris stretches more than 2,500 miles (4,000 km). EarthSky says that is nine times the length of Earth's Grand Canyon, and that Mars' canyon is also about 20 times wider and five times deeper. Mars is also home to the largest volcano in the solar system, Olympus Mons.

What this means for Mars science

The quake gave researchers two things at once. Co-author Doyeon Kim of Imperial College London said the same event offers a look at the center of the planet, through waves that crossed the core, and at an active fault under one of Mars' most striking landscapes.

It also shows that Mars is still geologically alive in some places. Watching for more marsquakes is not possible at the moment, however. InSight stopped operating in 2022 because dust built up on its solar panels, and no active lander is currently recording marsquakes on the surface.

Around Prague, based on reporting by EarthSky