Pit Crater

A pit crater, also called a collapse crater, is a depression formed when the ground above an underground void or empty chamber sinks or collapses, rather than by a volcanic eruption or the venting of lava. Pit craters occur on multiple planetary bodies, including Mercury, Venus, Earth, Mars, and the Moon, and unlike impact craters they lack a raised rim or ejecta blanket; on Earth they typically form through lava-tube collapse, magma-chamber drainage, or the failure of solid rock above a subsurface cavity, leaving a near-circular opening with steep, fissured walls.