Source: AGU Advances
The study of earthquakes and the seismic waves they generate offers profound insights into the Earth’s interior, but the wonders of seismology extend beyond our planet. During the Apollo missions to the Moon, seismometers collected invaluable data, laying the groundwork for understanding planetary geology. Similarly, when NASA’s Viking missions landed on Mars in 1976, they aimed not just to explore the Martian surface, but also to unravel its seismic secrets.
Despite the ambitious goals of the Viking program, the results were somewhat mixed. Viking 1’s seismometer unfortunately failed to deploy, rendering its intended measurements impossible. In contrast, Viking 2 managed to record seismic activity, but only captured two ambiguous events, leaving scientists yearning for clearer data.
Xiao et al. took a fresh look at these recorded events, cross-referencing them with data collected by NASA’s InSight lander, operational on Mars between 2018 and 2022. Their analysis indicated that one of Viking 2’s seismic events could indeed have been a genuine marsquake, emerging from a region of Mars that would later reveal nearly 1,000 marsquakes detected by InSight. This synchronicity paints a picture of a planet with a potentially active seismic past, bridging decades of exploration.
The primary objective of the Viking missions was to search for life on Mars, yet this pursuit is intricately linked with the planet’s geological history. Understanding seismology is crucial for revealing Mars’s internal structure and its tectonic activity, which together can inform scientists about the planet’s past habitability.
However, challenges arose during the Viking missions. The seismometer on Viking 2 was mounted on the lander’s deck, leading to significant noise interference from Martian winds. This unfortunate factor muddied the waters—whether the ambiguous seismic events recorded were genuine or simply the sounds of Mars’s breezes is still a matter of debate.
In stark contrast, InSight was placed directly on the Martian surface, optimizing its ability to detect seismic events without the distortion of wind noise. Over its operational period, InSight recorded more than 1,300 seismic occurrences, showcasing a wealth of data that Viking 2 could only dream of. The recent findings suggest continuity of seismic activity in the same region examined by Viking 2, underscoring that Mars has been seismically active over a 50-year span—initially detected by Viking and then extensively documented by InSight.
In summary, as researchers like Xiao et al. delve deeper into the seismic records of Mars, we’re gaining vital insights into the Red Planet’s geological evolution and, more broadly, its capacity to support life. The effort to understand martian seismology is not just a quest for knowledge but also a stepping stone in our long-term aspiration to ascertain life beyond Earth. This engaging interplay of past and present discoveries continually enriches our understanding of our neighboring planetary systems.
—Matthew R. Francis (@BowlerHatScience.org), Science Writer
