Seismic readings suggest a large subterranean reserve of liquid water on Mars.
PASADENA: Mars’ shattered igneous rocks may contain enough liquid water to fill an ocean the size of Earth’s surface.
That is the conclusion reached by scientists using seismic data collected by NASA’s robotic InSight lander during a mission to better interpret Mars’ innards. The water, which is buried roughly 7.2 to 12.4 miles (11.5 to 20 km) below the Martian surface, may have provided suitable conditions for microbial life in the past or in the present, according to researchers.
“At this depths, the crust is heated enough to contain liquid water. At shallower depths, the water would be frozen as ice,” said planetary scientist Vashan Wright of the University of California, San Diego’s Scripps Institution of Oceanography, lead author of the study, which was published on Monday in the journal Proceedings of the National Academy of Sciences.
“On Earth, we find microbial life deep underground, where rocks are saturated with water and there is an energy source,” said Michael Manga, planetary scientist and study co-author from the University of California, Berkeley.
The InSight lander landed in 2018 to research Mars’ deep interior, gathering data on the planet’s many layers, from its liquid metal core to its mantle and crust. The InSight mission concluded in 2022.
“InSight was able to determine the speed of seismic waves and how they vary with depth. The speed of seismic waves is determined by the rock’s composition, the location of cracks, and what fills the cracks. “We incorporated recorded seismic wave speed, gravity data, and rock physics models. The rock physics models are the same as those we use to estimate aquifer parameters on Earth or to map oil and gas reserves underneath.”
The results revealed the presence of a reservoir of liquid water amid fractured igneous rocks generated during the cooling and solidification of magma or lava in the Martian crust, the planet’s outermost layer.
“A mid-crust whose rocks are cracked and filled with liquid water best explains both seismic and gravity data,” according to Wright. “Water exists within fissures. If the InSight location is indicative and all the water is extracted from the fissures in the mid-crust, we predict that the water will create a 1-2 km deep (0.6–1.2 miles) ocean on Mars globally.”
The Martian landscape is currently frigid and bleak, yet it was previously warm and wet. That altered over three billion years ago. According to the study, much of the water on the Martian surface trickled down into the crust rather than escaping into space.
“Early Mars had liquid water on its surface in rivers, lakes, and possibly oceans. “The crust on Mars could have been full of water from very early on,” Manga said. “On Earth, groundwater underground infiltrated from the surface, and we anticipate that this will be comparable to Mars’ water history. This must have occurred when the upper crust was warmer than it is now.
Water would be a critical resource if humans ever sent astronauts to the Martian surface or established a long-term settlement. Mars’ polar regions and subsurface contain water in the form of ice. However, accessing the apparent subsurface liquid water would be challenging due to its depth.
“Drilling to these depths is extremely difficult. Looking for places where geological activity expels this water, such as the tectonically active Cerberus Fossae (a region in Mars’ northern hemisphere), is an alternative to looking for deep liquids,” Manga said, adding that concerns about protecting the Martian environment must be addressed.
