What explains earthquakes on Mars? – 10/18/2023 – Science

NASA’s InSight lander detected on May 4, 2022 the largest earthquake ever recorded on Mars, with a magnitude of 4.7 — modest by Earth standards, but strong for our planetary neighbor.

As Mars does not have the geological process of so-called plate tectonics, which generates earthquakes on our planet, scientists suspected that the impact of a meteorite had caused this tremor. But the search for an impact crater yielded no results, leading scientists to conclude that this earthquake was caused by tectonic activity — movements within the planet — and gave them a deeper understanding of what makes Mars shake.

“We concluded that the largest Mars earthquake observed by InSight was tectonic, not an impact. This is important as it shows that faults on Mars can host large tremors,” said planetary scientist Ben Fernando of the University of Oxford in England , lead author of the research published this week in the journal Geophysical Research Letters.

“There are still active faults on Mars. The planet is still slowly shrinking and cooling, and there is still movement within the crust, although there are no longer active plate tectonic processes. These faults can trigger earthquakes,” Fernando said.

The researchers pointed out that the 4.7 magnitude earthquake had its epicenter in the Al-Qahira Vallis region, in the southern hemisphere of Mars, approximately 2,000 km southeast of InSight’s location. They believe the tremor originated perhaps a few tens of km below the surface.

With future human missions to Mars in mind, a greater understanding of Martian seismic activity is pertinent.

“Each seismic event detected by InSight is a valuable piece of the puzzle, but this particular event plays a crucial role in revealing the geological history of the Red Planet, shedding light on its interior and its evolution,” said Constantinos Charalambous, planetary scientist from Imperial College London, co-author of the study and co-chair of the InSight Geology Working Group.

“In addition, it provides essential information about the distribution of seismic activity on Mars, which is a vital consideration for planning future human missions to the planet.”