maar

noun Geology.

1. a circular volcanic landform resulting from explosive ash eruptions.

noun plural maars or maare (ˈmɑːrə)

1. (sometimes capital) a coneless volcanic crater that has been formed by a single explosion

1. A broad, shallow, generally flat-floored volcanic crater that is often filled with water. Maars usually form from explosive eruptions caused by the heating and boiling of groundwater that is invaded by rising magma.