Scientists Surprised By Source of Largest Quake Detected on Mars
An anonymous reader shares a report: On May 4, 2022, NASA's InSight lander detected the largest quake yet recorded on Mars, one with a 4.7 magnitude -- fairly modest by Earth standards but strong for our planetary neighbor. Given Mars lacks the geological process called plate tectonics that generates earthquakes on our planet, scientists suspected a meteorite impact had caused this marsquake. But a search for an impact crater came up empty, leading scientists to conclude that this quake was caused by tectonic activity -- rumbling in the planet's interior -- and giving them a deeper understanding about what makes Mars shake, rattle and roll. "We concluded that the largest marsquake seen by InSight was tectonic, not an impact. This is important as it shows the faults on Mars can host hefty marsquakes," 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. "We really thought that this event might be an impact." "This represents a significant step forward in our understanding of Martian seismic activity and takes us one step closer to better unraveling the planet's tectonic processes," added Imperial College London planetary scientist and study co-author Constantinos Charalambous, co-chair of InSight's Geology Working Group. NASA retired InSight in 2022 after four years of operations. In all, InSight's seismometer instrument detected 1,319 marsquakes. Earth's crust - its outermost layer - is divided into immense plates that continually shift, triggering quakes. The Martian crust is a single solid plate. But that does not mean all is quiet on the Martian front. "There are still faults that are active on Mars. The planet is still slowly shrinking and cooling, and there is still motion within the crust even though there are no active plate tectonic processes going on anymore. These faults can trigger quakes," Fernando said.
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