We had a firehose of reports from the fourth planet, starting with a Hesperian (3.5 Bya) ocean. The InSight lander has been delivering the best of the goods: magma under Cerberus Fossae, that Christmas Eve quake now spotted as a meteor upon Amazonis, and a a 1810 km radius liquid core also known to us from InSight (and perhaps partly because of that meteor). Update reference materiel as necessary.
According to Mars Reconnaissance Orbiter, which has the before-and-after: the meteor gouged out a hole 150 m wide and 21 m deep. The rock was probably between 5-12 m wide assuming standard (also Mars-intersecting) composition; this wouldn't have survived Earth's atmospheric passage (nor Venus'). Its impact excavated several boulders out to 37 km away, some water-ice which surprises me given its 25ish° N latitude which the Chinese had marked in the desert band. But then: our robots don't dig twenty meters down. I have to ask if our colonists can dig this far but maybe they can just settle near another crater and use... a ladder.
We're lucky we have this seismic snapshot on account InSight - starting November 2018 - doesn't have long left to it.
UPDATE 10/18/23: 4 May '22 on the other hand was not impactful.
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