Viking 2's 50-Year-Old Signal May Be the First Marsquake Recording 2026

In 1975, NASA launched the Viking 1 and Viking 2 probes to Mars with the primary goal of searching for signs of life. To assess whether Mars was or had ever been habitable, studying its geological composition and potential seismic activity was crucial. Both probes carried seismometers for this purpose, but technical issues plagued the instruments: Viking 1's seismometer failed to deploy correctly, and Viking 2's captured too much interference to reliably determine if marsquakes were being detected. The signals were largely forgotten—until now. Fifty years later, a team of Chinese scientists has reexamined the data and identified what may be the oldest existing recording of a marsquake.

The Challenge with Viking 2's Seismometer

Viking 2's seismometer was mounted directly on the lander, which was susceptible to wind-induced movement. This caused vibrations to be transmitted to the seismometer much like a sail catching the wind, making it nearly impossible to distinguish ground motion from wind interference. Additionally, the lander's only contact with the Martian surface was through its legs, which could introduce further noise as vibrations traveled to the instrument. These factors rendered the seismic data highly unreliable, and the scientific community largely dismissed it.

NASA's Lessons and the InSight Mission

NASA learned from the Viking experience. In 2018, the agency sent the InSight lander to Mars, equipped with a highly sensitive seismometer designed to be placed directly on the surface. This setup minimized interference and allowed InSight to detect hundreds of marsquakes, providing unprecedented insights into Mars's interior structure. The success of InSight demonstrated the value of dedicated seismic monitoring on Mars. Context on how this played out before sits in Viking 2's 50-Year-Old Signal May Be the First Marsquake Recording.

Reevaluating the Viking 2 Data

The Chinese research team applied modern analytical techniques to the decades-old Viking 2 recordings. By carefully filtering out noise and accounting for the lander's structural response, they identified a signal that closely resembles known marsquake patterns. This signal, if confirmed, would predate the InSight detections by more than 40 years, offering a new window into Mars's seismic history. The background to this story is set out in Mars Magma Discovery Suggests Hidden Habitable Potential. A related thread runs through Mars Magma Rivers Boost Chances for Life, Study Finds.

Key Takeaways

• Viking 2's seismometer recorded data that was previously considered too noisy for reliable analysis.
• Modern signal processing has enabled scientists to extract potential marsquake signals from the old data.
• The finding could extend the timeline of known marsquake activity back to the 1970s.
• InSight's success highlights the importance of proper instrument deployment for seismic studies.
• Reanalysis of historical data can yield valuable scientific discoveries.

Why This Matters for Mars Exploration

Understanding marsquakes helps scientists probe the planet's internal structure and composition. Seismic waves travel through different materials at varying speeds, revealing details about Mars's crust, mantle, and core. If the Viking 2 signal is indeed a marsquake, it provides an additional data point that could refine models of Martian seismicity. Moreover, it demonstrates the enduring value of archival data and the potential for new discoveries from old missions. Earlier coverage in Mars Magma Rivers Boost Habitability Prospects for Rocky Planets shows how the argument developed. A closer look at the same subject appears in Perseverance Sets Record for Longest Distance Driven on Mars.

Comparison of Mars Seismometers

What to Watch Next

Further analysis of the Viking 2 data will be needed to confirm the signal's seismic origin. Independent teams may attempt to replicate the findings using different noise-reduction techniques. Additionally, future Mars missions could deploy more advanced seismometers to build on both Viking and InSight legacies, potentially leading to a permanent seismic network on the Red Planet. Anyone following the wider picture can start with Science: latest articles. The same theme surfaces in NASA's Vulcan Exoplanet Was a Stellar Illusion, Not Spock's World, which takes a different angle.