Earth has over 200 large craters or astroblemes.

     When a large meteoroid enters Earth's atmosphere, it's traveling at about 10 miles per second.  It usually breaks up into several pieces in flight.  At the moment of impact, a massive shock wave is sent downward into the rock and upward into the meteorite.  The rock is now impacted into less than half of the original size.  After the initial shock wave, an explosion caused by a decompression wave throws rock outward onto the rim and surrounding area.  Most of the meteorite vaporizes in the explosion and throws tiny metal spheroids and fragments outward to the surrounding area.  The main mass of the meteorite is reduced to spheroids.  There is a large dust cloud caused by the impact which rains rock and meteorite dust over the crater.

     If no meteorite material is found, the crater was formed by a comet.  Comets are basically giant snowballs.