phre·​at·​ic frē-ˈa-tik How to pronounce phreatic (audio)
: of, relating to, or being groundwater
: of, relating to, or being an explosion caused by steam derived from groundwater

Examples of phreatic in a Sentence

Recent Examples on the Web In that case, the ongoing seismic activity could stop abruptly or peak in a phreatic eruption—the volcano would spurt out hot liquids, gases and rock fragments instead of lava. Alessio Perrone, Scientific American, 4 Dec. 2023 The blast at Whakaari in 2019, the explosion on Japan's Intake in 2014, a phreatic eruption on the Philippine's Mayon in 2013 -- all of these events killed people who should likely not have been so close to a potentially explosive and active volcano. Erik Klemetti, Discover Magazine, 4 Dec. 2023 This all could mean that new magma is moving under Taal and this phreatic blast is just another sign that Taal is heading towards a potential new period of activity or larger explosions. Erik Klemetti, Discover Magazine, 12 Jan. 2020 Its eruptions range from phreatic (steam-driven) to Plinian—extremely explosive eruptions that can send volcanic debris tens of miles into the Earth’s atmosphere. Time, 15 June 2023 Now, this explosion may be a one-off at Kusatsu as many phreatic eruptions are. Erik Klemetti, Discover Magazine, 23 Jan. 2018 In fact, the eruption on Ontake in Japan that killed over 40 people in 2014 was also a phreatic explosion with little in the way of earthquakes or other signs an eruption could happen. Erik Klemetti, Discover Magazine, 23 Jan. 2018 Ontake has a limited history of phreatic explosions but so do most volcanoes in settings like Japan (or the Cascades for that matter). Erik Klemetti, Discover Magazine, 28 Sep. 2014 However, the evidence suggests that this eruption was phreatic—that is, driven by gas and steam, not new magma. Erik Klemetti, Discover Magazine, 13 Oct. 2016

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'phreatic.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Greek phreat-, phrear well; akin to Armenian ałbiwr spring, Old High German brunno — more at burn

First Known Use

circa 1890, in the meaning defined at sense 1

Time Traveler
The first known use of phreatic was circa 1890

Dictionary Entries Near phreatic

Cite this Entry

“Phreatic.” Dictionary, Merriam-Webster, Accessed 18 Apr. 2024.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!