When the meteor struck the ground, the hot and pressurized air around the meteor was the least of the black star's problems. Instead, all of the energy that the hammer possessed after falling from the limit of the sky became its most difficult problem to deal with.
All of the energy that the hammer possessed was forcefully injected into the ground when the hammer made contact with the ground. The ground couldn't handle all of the energy and was quickly overwhelmed.
The ground was shattered by the immense mechanical force, and the shattered part was melted by the immense heat energy. Then the pressurized air was infused into this melted part to cause a massive explosion that vaporized nearly everything in the vicinity.
The explosion was as if the mountain was erupting again. It didn't help that there was lava nearby, which was also thrown up by the explosion.
