With modern computing power and innovative analytical skills, scientists at Scripps Institution of Oceanography at UC San Diego and their colleagues have constructed the most detailed imagery to date of a massive active magma chamber located off the Pacific Northwest where Earth’s plates are spreading the seafloor apart.
Scientists including Scripps postdoctoral researcher Adrien Arnulf and researcher Alistair Harding, both based at the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics at Scripps, tapped into a trove of seismic data to uncover a magma reservoir comparable in size to California’s Yosemite Valley.
New details of the internal structure beneath Axial volcano, which erupts roughly every decade, are presented in a recent issue of the journal Geology.
Arnulf said Axial’s magma chamber, centered at the intersection of the Juan de Fuca Ridge and the Cobb hotspot chain, spans 14 kilometers (8.7 miles) long, three kilometers (1.8 miles) wide, and one kilometer (0.6 miles) thick.
“It’s the best picture of a volcano anywhere on the planet,” said coauthor Graham Kent, a Scripps alumnus now based at the University of Nevada, Reno.
Since the data were collected in 2002 from the research vessel Maurice Ewing, Kent said transformative new imaging and computing techniques have allowed the researchers to construct images with unprecedented fidelity. Kent likened the process to comparing details of a 20th century X-ray to a modern MRI.
The new images revealed a geometrically complex magma system that includes several never-before-imaged pathways that may transport magma to eruption sites on the earth’s surface and help relieve stress within the volcano. The images also revealed that only a small fraction of the magma in the giant reservoir is used during an eruption event.
The National Science Foundation and the Cecil H. and Ida M. Green Foundation supported the study. Coauthors include Suzanne Carbotte of Lamont-Doherty Earth Observatory; Juan Pablo Canales of Woods Hole Oceanographic Institution; and Mladen Nedimovic of Lamont-Doherty Earth Observatory and Dalhousie University.
-- Mario C. Aguilera