A tuff ring is a low, wide volcanic crater formed by the explosive interaction of magma with water, producing a ring of tuff (consolidated volcanic ash) around the vent. Tuff rings are significant in volcanology for understanding phreatomagmatic eruptions and the formation of volcanic landforms.
Reference: Lorenz, V. (1986). “On the Growth of Maars and Diatremes and Its Relevance to the Formation of Tuff Rings.” Bulletin of Volcanology, 48(5), 265-274.