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 eruption’s pyroclastic flows, for example, did not exceed 869℉ (465 ℃) and cooled far too slowly to create the glass. —Andrew Paul, Popular Science, 27 Feb. 2025

However, the findings of the new study suggest that the pyroclastic flows were not the first deadly phenomena that Vesuvius threw at Herculaneum—but such were instead preceded by a super-heated and short-lived ash cloud. —David Faris, Newsweek, 27 Feb. 2025

Unlike pyroclastic flows, which hug the ground, an ash cloud is airborne. —Katie Hunt, CNN, 27 Feb. 2025

The eruption triggered tsunamis and pyroclastic flows — fast-moving lava that flows down the volcano — and initially killed around 10,000 people. —Monica Cull, Discover Magazine, 2 Jan. 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