Warmer world and melting ice seen as volcano trigger

Graphic by the Facultad de Ciencias de la Tierra y el Mar, Universidad Nacional
The five clearly active volcanoes in Costa Rica.

A warming climate is now considered a cause of increased volcano activity.

This unexpected connection comes from German and U.S. scientists who have been studying the seabed off Central America.

The scientists said that it has long been known that volcanic activity can cause short-term variations in climate, but now they have found evidence that the reverse process also occurs: Climate affects volcanic activity. The study is now online in the international journal “Geology.”

The work is from the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany and from Harvard University in Cambridge, Massachusetts, U.S.A.

When the ice melts, the Earth spews fire, said a summary.

“In times of global warming, the glaciers are melting on the continents relatively quickly,” said Marion Jegen. “At the same time, the sea level rises. The weight on the continents decreases, while the weight on the oceanic tectonic plates increases. Thus, the stress changes within the earth to open more routes for ascending magma.”  He is a participant in the study and from the Kiel center.

The Collaborative Research Centre in Kiel has conducted extensive research in Costa Rica and offshore. They have released reports on the highly active volcanoes on the Pacific.

This latest study also comes from offshore where drilling recovered core samples that covered some  460,000 years, and researchers were able to spot layers of volcanic ash.

“There were periods when we found significantly more large eruptions than in others” said Steffen Kutterolf, the lead author of the Geology article. He was quoted in a Centre for Ocean Research summary of the research.

After comparing these patterns with the climate history, there was an amazing match, according to a center summary. The periods of high volcanic activity followed fast, global temperature increases and associated rapid ice melting, it said.

To expand the scope of the discoveries, Kutterolf and his colleagues studied other cores from the entire Pacific region, the center said. These cores had been collected as part of the International Integrated Ocean Drilling Program and its predecessor programs, and they record more than a million years of the Earth’s history, said the center. The drilling program has been the subject of a number of A.M. Costa Rica articles because some of the work is in the Pacific off this country’s coast.

“In fact, we found the same pattern from these cores as in Central America” said Jegen, a geophysicist.

The rate of global cooling at the end of the warm phases is much slower, so there are less dramatic stress changes during these times, said the center summary.

“If you follow the natural climate cycles, we are currently at the end of a really warm phase. Therefore, things are volcanically quieter now. The impact from man-made warming is still unclear based on our current understanding” said Kutterolf in the center summary.

The Coco tectonic plate is forcing its way under the lighter Caribbean plate on which Costa Rica rides.

That is why the country is considered to be part of the Pacific ring of fire. Sea levels are predicted to rise dramatically over the next 100 years, and this is likely to put more pressure on the Coco plate.

Costa Rica has five clearly active volcanoes, but there are many others than could show activity because they have in the past.

This entry was posted in Costa Rica News. Bookmark the permalink.