Shallow-crustal magma chamber beneath the axial high of the CoAxial Segment of Juan de Fuca Ridge at the source site of the 1993 eruption

• Published in: Geology (Boulder) 2002-04, Vol.30 (4), p.359-362
• Main Authors: Menke, William, West, Michael, Tolstoy, Maya
• Format: Article
• Language: English
• Subjects: applied (geophysical surveys & methods); Axial eruption 1993; Axial Seamount; CoAxial Segment; crust; East Pacific; eruptions; geophysical methods; geophysical profiles; geophysical surveys; Geophysics; Juan de Fuca Ridge; Lava; magma chambers; magma transport; magmas; melts; mid-ocean ridges; North Pacific; Northeast Pacific; ocean floors; oceanic crust; Pacific Ocean; plate tectonics; sea-floor spreading; seamounts; seismic methods; seismic profiles; Seismology; shallow depth; solid Earth (tectonophysics); spreading centers; submarine volcanoes; surveys; tomography; upper crust; Volcanoes
• ISSN: 0091-7613; 1943-2682
• DOI: 10.1130/0091-7613(2002)030<0359:SCMCBT>2.0.CO;2

Seismic imaging reveals a shallow-crustal magma chamber beneath the source site of the 1993 eruption on Coaxial segment, Juan de Fuca Ridge. The magma chamber is at least 6 km3 in volume and contains at least 0.6 km3 of melt, enough to supply at least several eruptions of a size equal to the one in 1993. No mid-crustal connection of this magma chamber with the magmatic plumbing of nearby Axial volcano (the current expression of the Cobb-Eickelberg hotspot) is evident, confirming previous geochemical and geological studies that argued against mixing between the two. The lack of connectivity implies that magma transport through the uppermost mantle and lower crust are very highly focused into narrow (