The eruption of Russia's Sarychev Volcano in June 2009, as seen from above. New research suggests major eruptions can influence the flow of global rivers. Photo by NASA
EDINBURGH, Scotland, Oct. 5 (UPI) -- A new study, published this week in the journal Nature Geoscience, offers the first exploration of the relationship between major river flows and volcanic eruptions.
Previous research has suggested that major volcanic eruptions can cause a shortage of precipitation in places around the world. Volcanic ash can block sunlight and thwart rain cloud formation. Researchers at the University of Edinburgh looked at how this climatic domino-effect influences rivers.
Scientists compared the historic flow data for the world's 50 largest rivers with a timeline of modern volcanic eruptions, spanning from Krakatoa in 1883 to Pinatubo in 1991. Rivers were organized by region, so scientists could get a better sense of which were likely to be most influenced by a given eruption. Computer models analyzed the relationship between eruptions and rainfall totals.
The results of their study showed that volcanic eruptions can promote less rain and lower flows in some regions, while encouraging heavier rains and higher flows in others.
In tropical regions and northern Asia, including rivers like the Amazon, Congo and Nile, droughts and low-flows were mostly likely to follow in the one or two years after a major eruption.
But in sub-tropical regions, including the American Southwest and parts of South America, heavier rains and higher flows were more likely -- the result volcano-induced disruptions of global atmospheric circulation patterns.
"Our findings reveal the indirect effect that volcanoes can have on rivers, and could be very valuable in the event of a major volcanic eruption in future," study author Carley Iles, a geosciences researchers at the University of Edinburgh, said in a press release.