pyroclastic

American  

[pahy-ruh-klas-tik] / ˌpaɪ rəˈklæs tɪk /

adjective

Geology.

1. composed chiefly of fragments of volcanic origin, as agglomerate, tuff, and certain other rocks; volcaniclastic.

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pyroclastic British  

/ ˌpaɪrəʊˈklæstɪk /

adjective

1. (of rocks) formed from the solid fragments ejected during a volcanic eruption

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pyroclastic Scientific  

/ pī′rō-klăs′tĭk /

1. Composed chiefly of rock fragments of explosive origin, especially those associated with explosive volcanic eruptions. Volcanic ash, obsidian, and pumice are examples of pyroclastic materials.

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Etymology

Origin of pyroclastic

First recorded in 1885–90; pyro- + clastic

Example Sentences

The rise and collapse of the eruption column presaged a series of pyroclastic surges, the fourth of which killed everyone in its path in Pompeii.

From The Wall Street Journal • Jan. 2, 2026

Footage shared throughout Monday shows a rapidly moving mix of ash, gas and rock - known as a pyroclastic flow - emerging from the site and moving down the side of the volcano.

From BBC • Jun. 2, 2025

The temperature of the pyroclastic flows that buried Herculaneum and Pompeii was several hundreds of degrees Celsius, hot enough to easily burn and destroy soft tissue.

From Salon • Mar. 4, 2025

For volcanoes on land, geologists understand the sedimentation mechanism of pyroclastic flows well, but the sediments themselves get lost easily due to erosion.

From Science Daily • Feb. 22, 2024

The initial pyroclastic flow and blasts expired within minutes, but the vertical eruptions went on throughout the day.

From "Mountain of Fire" by Rebecca E. F. Barone