When is a crater not a crater? Answer....when it's a pseudo-crater! Like real craters, they are formed during a volcanic eruption. When flowing lava creates a lava field, sometimes the lava will flow over wet ground, e.g., a swamp, a pond, a lake. The water below the lava heats up creating eruptions of steam that burst through the lava forming these pseudo-craters. Pseudo-craters are found in the Lake Myvatn area of Iceland and on Mars!