During its four years of life, the InSight lander recorded more than 1300 “marsquakes.” Most of them were tiny, and most were caused by space rocks slamming into Mars. But the largest quake it ever felt came from the planet’s insides, far below the surface. That’s an indication that Mars isn’t dead yet.

The quake took place in May of 2022, just a few months before InSight’s mission ended. It was magnitude 4.7. By Earth standards, that’s not much – maybe strong enough to feel, but not strong enough to cause any damage. But by Mars standards, it was a whopper – five times more powerful than the second-strongest quake. And it rattled around the planet for six hours.

The quake was centered about 1400 miles away from InSight, in a region with a rugged surface. At first, scientists suspected the quake was caused by a large meteorite impact. That would’ve created a crater a thousand feet across, and blown away dust on the surface for miles around.

So they scoured pictures taken by eight spacecraft in orbit around Mars. But they didn’t find a thing – no crater, no blast zone. That means the quake probably originated inside the planet, at a depth of about 11 to 17 miles. It might have been triggered by movement along a fault line. So even though the Martian crust isn’t made of moving plates, as Earth’s is, there may still be a good bit of shakin’ and rattlin’ below the surface of Mars.
 

Script by Damond Benningfield

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