This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Earthquakes and the seismic waves they generate provide some of the best clues to Earth's interior. To extend that success to other worlds, scientists placed seismometers on the Apollo missions to the moon and on the Viking Mars landers, which reached Mars in 1976.
Though the Apollo detectors proved a resounding success, Viking's results on Mars were less clear: Viking 1's seismometer failed to deploy properly, and Viking 2 recorded only two ambiguous events. Xiao and team reassessed these events and compared them to data collected by NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander, which operated on the surface of Mars between 2018 and 2022. The authors showed that one Viking 2 event could have been a real marsquake, originating from the same region where InSight recorded nearly 1,000 marsquakes decades later.
The findings are published in the journal AGU Advances. Viking was primarily a mission to search for life on Mars, but that question was closely tied to the planet's geological evolution. Seismology could reveal Mars's internal structure and tectonic activity, helping scientists reconstruct the history that shaped its habitability.
However, Viking 2's seismometer was mounted on the lander's deck, so it picked up a lot of wind noise. It remains uncertain whether either of the two ambiguous events it reported was a true marsquake or simply wind-related noise. InSight's seismometer, placed directly on the ground, later detected more than 1,300 seismic events.
The new study suggests that one Viking event could, indeed, have been a marsquake from the same region where InSight later recorded a swarm of nearly 1,000 marsquakes—suggesting that the region was seismically active both in the Viking era and nearly 50 years later. Wanbo Xiao et al., Fifty Years Later: Revisiting Viking 2 Seismic Signals Through InSight, AGU Advances (2026). DOI: 10.1029/2026av002319 MA in English, copy editor since 2021 with experience in higher education and health content.
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