(obsolete,geology) Flowingmud associated with avolcaniceruption (especially inSouth America), formed when snow or a lake near a volcano is disrupted, or when rain or steam mixes with soil or ash during an eruption.[from 1800s–1930s]
1832,Samuel Hibbert,History of the Extinct Volcanos of the Basin of Neuwied, on the Lower Rhine, page40:
These are the principal tufas indicative of the boiling tufaceous mud, ormoya, which once filled, even to an overflow, the valley of Rieden.
