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August 22, 2016

Look! In the sky! It’s a bird, it’s a plane! Wait, run, it’s this week’s EarthWord!

EarthWords is an on-going series in which we shed some light on the complicated, often difficult-to-pronounce language of science. Think of us as your terminology tour-guides, and meet us back here every week for a new word!

Image shows gray ash covering cars and a house
Ash buries cars and buildings after the 1984 eruption of Rabaul, Papua New Guinea. Credit: USGS

The EarthWord: Tephra


  • Tephra is the general name given to anything thrown into the air during a volcanic eruption. It can range from individual ash particles all the way to volcanic bombs.


  • Tephra comes from the Ancient Greek tephra, meaning “ashes.”

Use/Significance in the Earth Science Community:

  • The various types of tephra can have far-ranging impacts on the environment and human society. Ash clouds can reach the upper atmosphere, temporarily lowering temperatures and potentially interrupting air travel. Cinders can blanket nearby ecosystems and communities, causing health problems and damaging infrastructure. And volcanic bombs can very actively and directly damage infrastructure.


Next EarthWord: It’s not just teens that like to rebel; sometimes it’s rock layers...

Hungry for some science, but you don’t have time for a full-course research plate? Then check out USGS Science Snippets, our snack-sized science series that focuses on the fun, weird, and fascinating stories of USGS science.

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