{"id":804212,"date":"2026-11-06T08:56:34","date_gmt":"2026-11-06T13:56:34","guid":{"rendered":"https:\/\/spaceweekly.com\/?p=804212"},"modified":"2026-11-06T08:56:34","modified_gmt":"2026-11-06T13:56:34","slug":"active-volcanoes-on-mars-noxious-gas-discovery-says-maybe","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=804212","title":{"rendered":"Active volcanoes on Mars? Noxious gas discovery says \u2014 maybe"},"content":{"rendered":"
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\nView larger. | Color-coded topographic map of the Alba Mons volcano (center) and surrounding region. Many cracks in the surface are visible around the volcano. The European Space Agency\u2019s Trace Gas Orbiter (TGO) detected the gas hydrogen chloride coming from some of the cracks. Are they evidence of active volcanoes on Mars? Image via NASA\/ JPL-Caltech\/ Arizona State University\/ Wikimedia Commons.<\/figcaption><\/figure>\n<\/div>\n
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Are there still active volcanoes on Mars?<\/strong> The planet\u2019s volcanoes are no longer erupting, but there could still be flowing magma underground.<\/li>\n
The European Space Agency\u2019s Trace Gas Orbiter<\/strong> has detected hydrogen chloride coming out of cracks in the surface in the Alba Mons volcano region.<\/li>\n
The noxious gas<\/strong> is often produced by hot magma moving below the surface on Earth.<\/li>\n<\/ul>\n
Science news, night sky events and beautiful photos, all in one place.<\/em> Click here to subscribe to our free daily newsletter.<\/strong><\/p>\n
Are there active volcanoes on Mars?<\/h3>\n
Mars\u2019 enormous volcanoes \u2014 including Olympus Mons, the largest in the solar system \u2014 are remnants of an active volcanic past. But, unlike Earth, Mars has no moving tectonic plates to continually reshape its surface. And so, for much of the space age, Mars has been considered a largely dormant world. <\/p>\n
But that picture has been changing. NASA\u2019s InSight lander detected more than 1,300 seismic events, revealing that Mars still experiences marsquakes. And evidence of relatively recent volcanic activity has been accumulating, too.<\/p>\n
Now, an international team of researchers says it has found perhaps the strongest evidence yet that Mars might still be volcanically active, with magma moving beneath its surface.<\/p>\n
The researchers said on November 4, 2026, that the European Space Agency\u2019s Trace Gas Orbiter (TGO) has detected the gas hydrogen chloride (HCl) above cracks in the Martian surface in the region of the Alba Mons volcano. Alba Mons is northeast of Olympus Mons.<\/p>\n
On Earth, magmatism \u2014 the movement of hot magma below the surface \u2014 often produces hydrogen chloride. It is a minor volcanic gas compared to water vapor, carbon dioxide, and sulfur dioxide from earthly volcanoes. But, on Mars, hydrogen chloride might be a major volcanic gas, according to scientists.<\/p>\n
The detection adds to previous evidence for active volcanism still occurring on Mars today. Even though Mars\u2019 volcanoes are no long erupting, magma could still flow deeper down.<\/p>\n
The researchers published their new peer-reviewed findings in Science Advances<\/em> on November 4, 2026.<\/p>\n\n
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Mars may not be geologically dead after all. ? Our ExoMars Trace Gas Orbiter has detected hydrogen chloride above volcanic fissures in the Alba Mons region, which scientists suggest could be linked to dormant volcanic activity beneath the surface. Read more: new.esa.int\/articles\/new\u2026<\/p>\n
\u2014 European Space Agency (@esa.int) 2026-11-05T08:50:58.722Z<\/p><\/blockquote>\n<\/div>\n<\/figure>\n
Traces of noxious gas point to possible active volcanoes on Mars<\/h3>\n
Trace Gas Orbiter detected the traces of hydrogen chloride above geologically fresh cracks in the surface in the Alba Mons region. The gas was at parts-per-billion levels, but still higher than expected (if future studies confirm it is there at all). The paper states:<\/p>\n
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Detections of hydrogen chloride at low altitudes, unexplained by observed atmospheric state and models, together with the geological context of the region, hint at an igneous origin of this gas.<\/p>\n
Mars is reputed to lack ongoing volcanic activity. However, marsquakes were revealed recently, and clues to volcanism younger than tens of million years have accumulated. While sulfur dioxide, so far undetected, could testify to ongoing eruptive activity, evidence of active magma chambers may be better identified by seepage of halogen gases, such as hydrogen chloride.<\/p>\n<\/blockquote>\n
Co-lead author Daniel M\u00e8ge at the Space Research Center of the Polish Academy of Sciences said:<\/p>\n
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Our findings suggest that Mars has retained enough internal heat to support volcanic activity until recently, and possibly still does.<\/p>\n
The Trace Gas Orbiter was able to find the smoking gun. It was like looking for a needle in a haystack. It\u2019s truly amazing that it spotted a handful of molecules from a perhaps intermittent source, whilst moving continuously along its orbit to monitor the whole martian atmosphere,<\/p>\n
A huge part of the work consisted of examining all the possible chemical processes going on in the martian atmosphere. We needed to be rigorous, critical and creative to explain the presence of hydrogen chloride. The data were complex, but also excellent brain food.<\/p>\n<\/blockquote>\n
\nView larger. | This Mars Express spacecraft view shows Olympus Mons on Mars, the largest volcano in the solar system. Mars\u2019 volcanoes might no longer be erupting, but it seems there may still be magma flowing beneath the surface. If so, Mars could still have active volcanic systems deep underground. Image via ESA\/ DLR\/ FU Berlin\/ J. Cowart.<\/figcaption><\/figure>\n<\/div>\n
Aerosols and seepage<\/h3>\n
Hydrogen chloride can be found virtually everywhere in the Martian atmosphere. But those observations are typically during warmer seasons, when the hydrogen chloride behaves as an aerosol. Aerosols are fine solid particles or liquid droplets in the atmosphere.<\/p>\n
This gas isn\u2019t seen as much during Mars\u2019 colder seasons because its molecules are quickly \u201cabsorbed\u201d by water ice crystals and disappear from the observations. But the detections at Alba Mons were<\/em> during the cold season. And the levels were much higher than anticipated. The gas was detected above geologically fresh new cracks in the surface around the volcano. The cracks were several hundred meters long, and tens of centimeters wide.<\/p>\n
The researchers said it\u2019s likely that the hydrogen chloride seeped into Mars\u2019 atmosphere from these cracks. That would make it volcanic in origin. The paper states:<\/p>\n
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Observations by Atmospheric Chemistry Suite led to the widespread observations of hydrogen chloride at part-\u00adper-\u00adbillion levels in the atmosphere of Mars during the warm perihelion period [when Mars was closest to the sun in its 2-year orbit], attributed to aerosol-\u00adatmospheric sources. Here, we report hydrogen chloride detections during the cold aphelion season [when Mars is farthest from the sun] that are isolated in the Alba Mons region.<\/p>\n
We also identify fresh and narrow (\n<\/p>\n<\/blockquote>\n
A supplementary to the main paper (pdf download) also states:<\/p>\n
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Localized aphelion detections of HCl at low altitudes, together with the geological context of the area, suggests an igneous origin of this gas and that the detections are made above the seepage.<\/p>\n<\/blockquote>\n
Icy buffer zone<\/h3>\n
It\u2019s possible that the hydrogen chloride doesn\u2019t come straight from the magma. It might come from a buffer zone, a layer of permafrost above the magma.<\/p>\n
In the cold winter, the ice traps the hydrogen chloride molecules. But when the temperatures get a bit warmer in spring, the ice sublimates and release the gas into the atmosphere.<\/p>\n
If there is a permanent source of hydrogen chloride in the surface \u201csoil,\u201d this could explain the seasonality of the observations and their binding to a certain area.<\/p>\n
\nView larger. | The possible chlorine cycle on Mars, including hydrogen chloride. Image via ESA.<\/figcaption><\/figure>\n<\/div>\n
The chlorine cycle<\/h3>\n
On both Earth and Mars, there was a chlorine cycle initiated by degassing<\/em> while the planets were still forming. In other words, as molten rock cooled and solidified, it released gases from the planets\u2019 interiors into their atmospheres.The paper states:<\/p>\n
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On Mars, as on Earth, the chlorine cycle initiated by volcanic degassing from the deep interior upon planetary accretion was fed by the subsequent volcanic eruptions, and, because of its high mobility and solubility, chlorine has been continuously recycled in water, sediments, permafrost, and ice clouds. However, contrary to Earth, the absence of recycling due to plate tectonics probably make the volcanic source the main input to the surface-\u00adatmosphere system on Mars. The topic addressed here is volcanism still contributing to this cycle on Mars today?<\/p>\n
The more we know about Mars, the more we learn that it\u2019s not as cold and dead as we thought it was. While the surface is a cold desert, there might still be heat deeper down. Heat from flowing magma that just might be able to melt ice and support life.<\/p>\n<\/blockquote>\n
Habitats for life?<\/h3>\n
Plus, hot magma deeper down could heat ice and create groundwater. So could there still be active hydrothermal systems, too? If so, they might provide habitable conditions for microbes below the surface. M\u00e8ge said:<\/p>\n
Looking for Martian life in the seeping fissures of the Alba Mons region would make a lot of sense. If hydrothermal systems are active, they could contain the ingredients and energy needed for microorganisms to develop, and shield microorganisms from the hostile and changing environment above the surface.<\/p>\n
Bottom line: Are there still active volcanoes on Mars? New detections of hydrogen chloride from below the surface suggest flowing magma.<\/p>\n
Source: Enigmatic HCl detections as a potential signature of igneous activity on Mars<\/p>\n
Via:<\/p>\n
Institute of Space Research Russian Academy of Sciences<\/p>\n
ESA<\/p>\n
AAAS\/ EurekAlert!<\/p>\n
Read more:<\/p>\n
Did the Viking 2 lander detect marsquakes in 1976?<\/p>\n
The most recent volcanoes on Mars were surprisingly active<\/p>\n
Huge magma systems on Mars existed below the surface<\/p>\n
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Paul Scott Anderson<\/h4>\n
View Articles\n <\/p><\/div>\n
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About the Author:<\/h6>\n
Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan\u2019s Cosmos. He studied English, writing, art and computer\/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.
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\nWhile interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.
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\nHe has been writing for EarthSky since 2018, and also assists with proofing and social media.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n
![\"Active](\"https:\/\/earthsky.org\/upl\/2025\/09\/Olympus-Mons-Mars-Express.jpeg\")
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