Seismic data from NASA’s InSight lander suggests liquid water may exist beneath Mars’ surface, supporting the potential for microbial life underground.
Are subterranean lifeforms possible on Mars? A new interpretation of Martian seismic data by Ikuo Katayama (Hiroshima University) and Yuya Akamatsu (Research Institute for Marine Geodynamics) suggests that liquid water may exist beneath the surface of Mars—raising the possibility that microbial life could survive there. “If liquid water exists on Mars,” Katayama says, “the presence of microbial activity” is possible.
Their analysis is based on data collected by SEIS (Seismic Experiment for Interior Structure), an instrument deployed by NASA’s InSight lander, which arrived on Mars in 2018. InSight is notable for placing a seismometer directly on the Martian surface using its robotic arm.
SEIS detects seismic waves generated by natural events such as Marsquakes and meteorite impacts. These waves, classified as P-waves, S-waves, and surface waves, travel through the planet and are used to map its internal structure. By studying how these waves move through subsurface layers, scientists can infer the composition and potential presence of materials like water.
Reading the Planet’s Interior
Scientists can use P-waves and S-waves to determine a lot about the rocks that make up Mars, including the density of the rocks or potential composition changes within the rocks. For example, S-waves cannot travel through water and move at a slower speed than P-waves.
Therefore, the presence, absence, and arrival time of S-waves can determine what the subsurface looks like. Moreover, P-waves can travel faster through higher-density material and slower through less dense material, so their velocity can help determine the density of the material the wave is traveling through, as well as if there are any changes in density along its path. The seismic data collected with SEIS shows a boundary at 10 km depth and 20 km depth from measured discrepancies in seismic velocity.
This boundary has previously been interpreted as sharp transitions in the porosity (the percentage of open space in a rock) or chemical composition of the Martian interior. However, Katayama and Akamatsu have interpreted these cracks as potential evidence for water within the Martian subsurface. The seismic data indicate a boundary between dry cracks and water-filled cracks in the Martian subsurface.
To test their hypothesis, they measured the seismic velocity passing through rocks with the same structures and composition of a typical Martian crustal rock under wet, dry, and frozen conditions. A typical Martian rock is similar to the diabase rocks from Rydaholm, Sweden, due to their evenly sized plagioclase and orthopyroxene grains.
Laboratory Experiments Support the Hypothesis
In the lab, Katayama and Akamatsu measured P-wave and S-wave velocity using a piezoelectric transducer, which uses “electrical energy . . . as a wave source” that “monitor[s] seismic wave energy” on dry, wet, and frozen diabase samples. Experimentation revealed that the seismic velocities of the dry, wet, and frozen samples are significantly different, which supports the interpretation that the boundary at 10 km and 20 km could be from a change from dry rock to wet rock.
These laboratory experiments back up Katayama and Yuya’s hypothesis that the boundary measured by seismic data indicates a transition from dry rock to wet rock rather than a change in porosity or chemical composition. The findings, therefore, provide compelling evidence for the existence of liquid water beneath the surface of Mars. “Many studies suggest the presence of water on ancient Mars billions of years ago,” Katayama explains, “but our model indicates the presence of liquid water on present-day Mars.”
Reference: “Seismic discontinuity in the Martian crust possibly caused by water-filled cracks” by Ikuo Katayama and Yuya Akamatsu, 24 September 2024, Geology.
DOI: 10.1130/G52369.1
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5 Comments
Nope.. it’s sandworms. Bank it.
…And for all ,the Sheldons out there, yes I’m joking.
I’m sure the Sheldons hear your Howard.
Yes, I missed you, too.
Let Musk up there. May he become the life on Mars. If only for a couple of minutes, before he croaks.
“Swedish Black Hjortsjö
Swedish Black Hjortsjö and Swedish Black Hjortsjö Coarse Grained are slightly grainier in structure, but with the same elegance as our black diabases.”
It would be a simpler crust, but mineralogically Mars is simpler.