Mega-Volcano, Magma Map Mark Seismic Advances
Discovering a mega-volcano on the floor of the Pacific Ocean is about as sexy as volcanology gets. But more often the scientific advances come from the drab confines of computer labs.
Both happened this week - Tamu Massif, a shield volcano the size of New Mexico, was mapped and described by a research team led by Texas A&M, based on a scientific cruise off the coast of Japan.
Meanwhile, a team from UC Berkeley and University of Maryland stayed home and ran a model on a supercomputer. They crunched seismic wave data from about 200 earthquakes to refine a model for how magma may flow and contribute to the volcanoes that create island chains and seamounts in the oceans worldwide. Their results were published Thursday in the online journal Science Express.
The resulting three-dimensional map suggests that magma plumes radiate in “fingers” thousands of miles long in Earth’s upper mantle, in patterns consistent with volcanic activity far from plate boundaries and spreading ridges. It is the most sophisticated worldwide magma map using data from multiple earthquakes.
Both teams were chipping away at the same conundrum: how magma flows and contributes to volcanic eruptions. The simplest model, ubiquitous in high school textbooks, shows balloons of hot, buoyant magma rising from Earth’s molten core as part of a large-scale convection cycle that creates a conveyor belt of tectonic plates creeping along over millions of years. Volcanoes erupt where these plates collide and slide under and over each other.