ESA data shows volcanic gas venting from Alba Mons on Mars

Mars holds underground magma chambers beneath its largest shield volcano rather than sitting as a geologically dead planet, according to data from the European Space Agency reported by afu.id on November 5, 2026. Researchers analyzing measurements from the ExoMars Trace Gas Orbiter detected hydrogen chloride gas venting through fractures on the slopes of Alba Mons, pointing to active volcanic seepage from beneath the Martian crust. The findings, published November 4 in the journal Science Advances, reveal that internal planetary heat continues to drive localized gas releases in patterns linked to seasonal ice sublimation.

ExoMars Orbiter Traces Volcanic Seepage at Alba Mons

Instruments aboard the Trace Gas Orbiter, specifically the Atmospheric Chemistry Suite, tracked concentrations of hydrogen chloride measuring several parts per billion above Alba Mons. The gas concentrations spiked during cold periods when Mars sat at its farthest point from the Sun, a window when dust-driven reactions should not occur. Additional surges appeared predictably at the start of Martian summer approximately two kilometers above north-facing fractures on the volcano.

The repetitive annual cycle across specific fissure locations convinced researchers the source originates deep within the planet rather than from surface dust storms. During winter months, ice seals the volcanic vents and traps underground gases beneath the surface. As summer temperatures rise, that ice sublimates directly into vapor, releasing the trapped gas into the thin atmosphere at a rate of less than three kilograms per second. Daniel Mège, a planetary scientist at the Space Research Centre of the Polish Academy of Sciences and the University of Bern in Switzerland, stated that volcanic seepage represents the most likely origin for the hydrogen chloride.

Magma Reservoirs and Clues to Martian Climate History

Alba Mons stands as the widest shield volcano in the northern hemisphere of Mars, while Olympus Mons holds the title of the tallest volcano in the solar system. Networked cracks surrounding Alba Mons serve as conduits for gases escaping from a dormant magma chamber below.

The discovery aligns with prior orbital imagery showing young volcanic deposits near Elysium Planitia, alongside marsquakes recorded in the same region by NASA’s InSight lander. Mège noted that the planet has retained enough internal heat to sustain volcanic activity into recent geological epochs. Historical models suggest that ancient volcanic emissions of gases such as hydrogen chloride helped thicken the early Martian atmosphere and warm the climate sufficiently to allow liquid water to flow across the surface.

Alba Mons Fracture Zones Targeted for Future Missions

The presence of warm magma interacting with ground ice or subsurface water creates the theoretical conditions for active hydrothermal systems. On Earth, comparable geothermal environments support thriving microbial communities in deep groundwater and hydrothermal vents. Consequently, scientists have identified the Alba Mons fracture zones as high-priority targets for future life-detection missions.

Despite the implications for astrobiology, researchers emphasized that the detection does not signal an active volcanic eruption or prove the existence of biological life. The hydrogen chloride data confirms only that thermal energy persists deep inside the planet.