We may not have detected any life on Mars yet, but the planet has seismic activity. Insight has detected seismic movements, the first direct evidence of Martian earthquakes (Marsquakes), the results of which have been published in a series of articles in a special issue of Nature magazine dedicated to our neighbouring red planet.
Data from NASA’s Mars Insight lander, which landed in the Elysium Planitia region of Mars on November 26, 2018 (and with a budget of $850 million), has detected hundreds of Martian earthquakes in just ten months, some (about 20 events) of which reached three or four on the Richter scale.
Why is this discovery important?
Scientists were not surprised that Mars is seismically active: the main goal of the Insight mission, after all, was to place a seismometer on Mars and explore the depths of the planet through vibrations. However, until Insight began to detect these earthquakes, there was no evidence that they existed: scientists had only theorised. Now there is proof that Mars is "alive".
"We are using geophysics to explore the deep interior of Mars. For the first time, we have established that Mars is a seismically active planet,” stated Bruce Banerdt of NASA’s Jet Propulsion Laboratory (JPL) and the leader of one of Nature’s research.
Even if we had detected earthquakes of a magnitude of three or four, if we were on Mars, we would not have noticed them, perhaps a small movement, basically because events on Mars occur much deeper below the surface than on Earth. However, confirming that Mars is seismically active is exciting.
It is much less seismically active than Earth (which is considered a planet with high seismic activity) but more so than the Moon (which is considered a planet with seismically low activity).
Mars has no tectonic plates: so what produces these earthquakes?
Most earthquakes on Earth are associated with tectonic plates, however, on Mars which has no tectonic plates, most of these tremors are probably due to the slow cooling of the planet’s interior. "As the planet cools, it shrinks and the fragile outer layers fracture," Banerdt clarifies.
Analyses of the measurements of these Martian earthquakes and heat transport will allow the mission team to build a detailed 3D map of the Mars interior, NASA has explained. In addition, Insight scientists are using radio signals emitted from the lander to track how much Mars wobbles on its axis over time. This information will help determine how large and dense the planet’s core is.
Together, the results add to the existing evidence suggesting that Mars was once a very different planet. Meanwhile, Insight continues to monitor Martian earthquakes. "We now have 450 in our catalog," says Banerdt. This is just the beginning of the data and secrets that Insight can reveal about the red planet.
References: Journal References:
Banerdt, W.B., Smrekar, S.E., Banfield, D. et al. Initial results from the InSight mission on Mars. Nature Geoscience, 2020; DOI: 10.1038/s41561-020-0544-y
Johnson, C.L., Mittelholz, A., Langlais, B. et al. Crustal and time-varying magnetic fields at the InSight landing site on Mars. Nature Geoscience, 2020; DOI: 10.1038/s41561-020-0537-x
Banfield, D., Spiga, A., Newman, C. et al. The atmosphere of Mars as observed by InSight. Nature Geoscience, 2020; DOI: 10.1038/s41561-020-0534-0
Giardini, D., Lognonné, P., Banerdt, W.B. et al. The seismicity of Mars. Nature Geoscience, 2020; DOI: 10.1038/s41561-020-0539-8
Lognonné, P., Banerdt, W.B., Pike, W.T. et al. Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data. Nature Geoscience, 2020; DOI: 10.1038/s41561-020-0536-y
Golombek, M., Warner, N.H., Grant, J.A. et al. Geology of the InSight landing site on Mars. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-14679-1