Is there evidence for a cause and effect relationship between eruptions that occur at about the same time from volcanoes located hundreds to thousands of kilometers apart?

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Episode Number: 38

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Location Taken: US

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Welcome to CoreFacts, where we're always short on time and big on science. I'm Steve Sobieszczyk. Today's question is:

Is there evidence for a cause and effect relationship between eruptions that occur at about the same time from volcanoes located hundreds to thousands of kilometers apart?

No. Since there are on average between 50 and 60 volcanoes that erupt each year somewhere on Earth (about 1 every week), some of Earth's volcanoes may actually erupt within a few days or hours of each other. Upon closer inspection, however, the eruptions are almost always preceded by very different build-up periods in terms of time and type of activity. The "trigger" of this precursory activity is the key to understanding what causes an eventual eruption at any one volcano, not the timing of significant eruptions hundreds to thousands of kilometers apart.

According to the theory of plate tectonics, the location and frequency of volcanism on Earth is due primarily to the way in which our planet's surface is divided into large sections or plates and how they move relative to each other, and the formation of deep "thermal plumes" that rise from the core-mantle boundary about 3,200 kilometer below the surface. These mechanisms and the fact that even nearby volcanoes erupt magma with different and often unique chemical composition strongly suggests there is unlikely to be any cause and effect relationship between volcanic eruptions separated hundreds to thousands of kilometers apart.

And now you know. Join us again tomorrow as we'll give you yet another new CoreFact. If you're interested in previous CoreFacts, or would like to check out CoreCast, our in-depth science podcast, browse over to usgs.gov/podcasts. If you would like to contact us here at the show or submit a question you think we should answer on the air, you can email us at corefacts@usgs.gov or leave us a voicemail at 703-648-5600. Remember, long distance fees do apply.

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