Note that they are ALL exactly 10.0 km deep.
This is apparently the "detonation" depth of Rods of God.
“Instead of hundreds of small projectiles from a few thousand feet, Thor used a large projectile from a few thousand miles above the Earth. The “rods from God” idea was a bundle of telephone-pole sized (20 feet long, one foot in diameter) tungsten rods, dropped from orbit, reaching a speed of up to ten times the speed of sound.
The rod itself would penetrate hundreds of feet into the Earth, destroying any potential hardened bunkers or secret underground sites. More than that, when the rod hits, the explosion would be on par with the magnitude of a ground-penetrating nuclear weapon – but with no fallout.
It would take 15 minutes to destroy a target with such a weapon.”
More at:
https://www.popsci.com/scitech/article/2004-06/rods-god/