Mars could have an ocean's worth of water beneath its surface, seismic data suggest
Beneath Mars' surface, seismic data suggests a vast amount of water, possibly an ocean's worth.
Recent seismic data from NASA's InSight lander suggests that Mars might hold significant amounts of water between 7.1 and 12.4 miles below its surface. The seismic data collected by the SEIS instrument on Mars points to large quantities of liquid water buried deep underground, supporting theories of substantial ancient aquatic bodies on the Red Planet. This study, conducted by Ikuo Katayama from Hiroshima University and Yuya Akamatsu of the Research Institute for Marine Geodynamics in Japan, reveals seismic wave velocities indicating the presence of water. Their analysis suggests that the current-day Mars, despite its arid surface, could still host liquid water underground.
Katayama stated, "Many studies suggest the presence of water on ancient Mars billions of years ago. But our model indicates the presence of liquid water on present-day Mars." By focusing on the velocities of seismic waves detected during marsquakes, a conclusive claim was reached about the existence of liquid water within Mars' interior. These seismic activities were closely monitored using two types of waves: P-waves and S-waves. P-waves, which move faster, were observed alongside S-waves, slower waves that cannot travel through water. Such differential wave behavior was matched with the composition and density of materials below the ground surface, potentially filled with liquid water.
The researchers highlighted SEIS's role in the study, underlining its capabilities in distinguishing between P-waves, S-waves, and surface waves. Between 2018 and 2022, the SEIS instrument was operational on Mars under the InSight mission, collecting valuable seismic readings. Observing how these waves slowed or sped up as they traveled through Mars provided insights into the materials encountered, be it rock or water. In specific zones, sudden transitions in seismic properties were seen at depths of 6.2 to 12.4 miles, underscoring the presence of water in these regions.
An intriguing observation was how these seismic transitions potentially debunked earlier notions of purely volcanic materials or impact ejecta buried beneath the surface. The differences perceived in wave behaviors could indicate a transition from porous rock to solid rock, or more compellingly, to water-saturated rock. Tests carried out on diabase rocks from Rydaholm in Sweden further supported this hypothesis, as their seismic signatures under wet conditions were akin to those observed on Mars, suggesting a strong terrestrial analogy.
These findings propose that enough water may exist beneath Mars to form a global ocean reaching up to 1.24 miles deep. This amount of water, if accessible, might hold possible microbial life forms, although current technology is inadequate for reaching and exploring these depths. While speculative, the presence of subsurface water fuels hope for microbial ecosystems, broadening horizons for future Mars explorations and studies aiming to validate these seismic data interpretations.
Sources: NASA, Hiroshima University, Research Institute for Marine Geodynamics, Geology journal