under water volcanoes

A new study from scientists at the Lamont-Doherty Earth Observatory at Columbia University has uncovered novel information about seafloor volcanoes, namely that these structures are not the “gentle giants of the planet.” Instead, these seafloor volcanoes can erupt at fairly regular cycles, every two weeks to 100,000 years during the first six months of each year, in a process that likely influences our climate.

Maya Tolstoy, one of the study’s co-authors said in a statement, “People have ignored seafloor volcanoes on the idea that their influence [on climate change] is small — but that’s because they are assumed to be in steady state, which they’re not.”

According to an article from LiveScience, undersea volcanoes are made “where magma (molten rock) rises to fill the gap between moving tectonic plates.” As the plates move, new crust “cools, cracks and sinks,” thus creating the gaps customarily seen between volcanoes. Indeed, undersea volcanoes have been said to resemble the stitching on a baseball mitt given that they stretch for nearly 37,000 miles on the seafloor in a criss-cross pattern, while producing 8 miles more lava than land volcanoes.

To study the behavior of these undersea volcano ridges, Tolstoy used real-time monitoring of underwater volcanoes and collected data from 10 volcanoes with seismographs, a tool to measure volcanic activity. Nearly a year later, she retrieved most of her instruments and upon analysis found “connections between ice age cycles and these seafloor corrugations,” extending back approximately 800,000 years. As the sea level drooped, more lava erupted from ridge volcanoes, thus expanding glaciers and creating thicker crust or higher topography. When sea levels rose, eruptions decreased, resulting in thin crust. Amazingly, these bands of thicker and thinner crust correspond to the Earth’s ice age cycles.

But Tolstoy believes that the differences in topography are not due to the sea level alone, but are also influenced by gravitational forces. As again described in the Columbia press release, “When the [earth’s] orbit is more elliptical, Earth gets squeezed and unsqueezed by the sun’s gravitational pull…a process that…massage[s] undersea magma upward.”

Ultimately, Tolstoy’s finding suggests that undersea volcanoes, like their land counterparts, may strongly influence climate change. She has said, “If you look at the present-day eruptions, volcanoes respond even to much smaller forces than the ones that might drive climate.” If undersea volcanoes erupt with such regularity, the eruptions could create enough CO2 to influence the earth’s temperature.

(Photo courtesy of NASA)