A pseudocrater, or rootless cone, at Mývatn, a volcanic landform which resembles a true volcanic crater, but differs in that it is not an actual vent from which lava has erupted.
They are characterized by the absence of any magma conduit which connects below the surface. They are formed by steam explosions as flowing hot lava crosses over a wet surface,
such as a lake. The explosive gases break through the lava surface and create crater-like forms.