Near Alba Mons, a volcano long written off as dead, hydrogen chloride gas keeps returning each Martian summer — and scientists think magma is to blame. A study published this week in Science Advances links the recurring detections to a likely active magma source below the surface, De Standaard reported.
An Anomaly That Kept Coming Back
Normally, the gas forms when water vapor reacts with sodium chloride from dust during massive southern hemisphere dust storms.
Then came 2020. The gas appeared in the northern hemisphere during its summer — no dust storm to explain it. The same anomaly returned in 2021. And again in 2022.
Researchers traced the plumes to Alba Mons, a vast ancient volcano long considered dormant. The study concludes that volcanic activity is the most probable explanation for the recurring detections. On Earth, hydrogen chloride also forms in underground magma chambers, leading scientists to suspect a similar process beneath Alba Mons.
Why Only in Summer? Blame the Ice
The seasonal timing puzzled researchers — until they looked at the ice.
The study identifies fissures up to 100 meters long and several meters wide in satellite images. Along some fractures, the soil shows lighter discoloration — what Wilson attributes to “local degassing,” much like the fumaroles near Naples. The ground itself, in other words, is showing its work.
A ‘Smoking Gun’ Years in the Making
The finding did not arrive out of nowhere. Sam Poppe, a planetary geologist at the Polish Academy of Sciences, who was not involved in the study, noted that solidified lava has recently been found elsewhere on Mars that could be less than a million years old. NASA’s InSight lander has also recorded seismic activity characteristic of underground magma flows.
Poppe called the hydrogen chloride detection a “smoking gun for volcanic activity.” Moving magma, gas release, surface deformation — everything is in place for an eruption, he said. But he added a caveat: the Martian surface has remained largely unchanged for hundreds of thousands of years, suggesting the last eruption was long ago.
Mars Still Has Active Volcanoes
The findings challenge the long-held view of Mars as a geologically dead planet. An eruption is unlikely imminently, but the study confirms the Red Planet retains internal heat — and activity.
In Poppe’s assessment, Mars has moving magma and outgassing — everything, he said, is present for an eruption.
The researchers behind the study argue that the recurring hydrogen chloride detections in the northern hemisphere summer point to an active magmatic source beneath Alba Mons. Five years after the first detection, they conclude that Mars still has active — if dormant — volcanoes, a finding that challenges the long-held picture of the planet’s current geological state.
