pyroclastic

adjective

py·​ro·​clas·​tic ˌpī-rō-ˈkla-stik 

: formed by or involving fragmentation as a result of volcanic or igneous action

Examples of pyroclastic in a Sentence

Recent Examples on the Web

The now-viral eruption culminated in an explosion of gas, debris, fountains of lava and a pyroclastic flow that swept across around 1.2 miles from the volcano’s southwestern crater, according to the Associated Press’ Colleen Barry. —Margherita Bassi, Smithsonian Magazine, 4 June 2025

However, pyroclastic flow deposits mantle the valleys around the volcano. —Erik Klemetti, Discover Magazine, 19 Mar. 2025

The most recent pyroclastic flows with significant reach were recorded on Feb. 10, 2022, Oct. 23, 2021, Dec. 13, 2020 and Feb. 11, 2014, Marco Viccaro, president of Italy’s national volcanology association, said Tuesday. —Colleen Barry, Los Angeles Times, 3 June 2025

Other footage showed pyroclastic flow — a combination of volcanic gas, lava blocks, ash and pumice that moves at an extremely high speed — rushing down the volcano. —Natalia Senanayake, People.com, 3 June 2025

Word History

Etymology

probably from pyro- + clastic

Note: The term was introduced by the English geologist Joseph Beete Jukes (1811-69) in The Student's Manual of Geology, new edition (Edinburgh, 1862), p. 68: "The word 'ash' is not a very good one to include all the mechanical accompaniments of a subaerial or subaqueous eruption, since ash seems to be restricted to a fine powder, the residuum of combustion. A word is wanting to express all such accompaniments, no matter what their size or condition may be, when they are accumulated in such mass so as to form beds of 'rock.' We might call them perhaps 'pyroclastic materials'…." In the index pyroclastic is glossed as "broken from fire."

First Known Use

1862, in the meaning defined above

Rhymes for pyroclastic

• anaplastic
• bioclastic
• fibroblastic
• hyperplastic
• hypoplastic
• inelastic
• lymphoblastic
• neoplastic
• orgiastic
• periphrastic
• predynastic
• superplastic