By Walt Hickey Marsquakes The InSight lander successfully deployed on Mars 15 months ago, and since then has detected over 450 marsquakes. Monday saw the publication of the initial findings about the Martian interior: the surface crust is about 16 feet of rocky grit, then about 3.1 miles of bedrock, then anywhere from 3.1 miles to 18.6 miles of slightly magnetic rock, and then the Martian mantle, which remains a mystery. Mars registers two tiny quakes per day, substantially less than Earth, which has 14,000 sizable earthquakes per year. Of 174 marsquakes analyzed, about 150 are seriously small. One reason is that marsquakes originate much deeper than on Earth, and some may just be impacts of meteors.