| Publications | | » | 41. R2K Advances in Seismic Imaging
Oceanography, 2012
 | | » | 40. R2K Seismic Studies
Oceanography, 2012
| | » | 39. Melt bodies off the EPR
Nature Geoscience, 2012
| | » | 38. JdF Plate: Gravity structure
G-cubed, 2011
| | » | 37. JdF Plate: Layer 2B structure
G-cubed, 2011
| | » | 36. Kane waveform tomography
GRL, 2010
| | » | 35. Kane Oceanic Core Complex
G-cubed, 2009
| | » | 34. Geophysical signatures of oceanic core complexes
GJI, 2009
| | » | 33. Accretion of the lower crust
Nature, 2009
| | » | 32. Faulting of the Juan de Fuca plate
EPSL, 2009
| | » | 31. Axial topography os the Galapagos Spreading Center
G-cubed, 2008
| | » | 30. Juan de Fuca Ridge flanks
G-cubed, 2008
| | » | 29. Seismic structure of oceanic core complexes
G-cubed, 2008
| | » | 28. Juan de Fuca Ridge: structure and hotspots
G-cubed, 2008
| | » | 27. Structure of the TAG segment, Mid-Atlantic Ridge
G-cubed, 2007
| | » | 26. Detachment faulting at TAG, Mid-Atlantic Ridge
Geology, 2007
| | » | 25. Structure of the Endeavour segment, Juan de Fuca Ridge
JGR, 2007
| | » | 24. Magma beneath Lucky Strike Hydrothermal Field
Nature, 2006
| | » | 23. Magma chamber of the Cleft segment, Juan de Fuca Ridge
EPSL, 2006
| | » | 22. Topography and magmatism at the Juan de Fuca Ridge
Geology, 2006
| | » | 21. Structure of the southern Juan de Fuca Ridge
JGR, 2005
| | » | 20. Sub-crustal magma lenses
Nature, 2005
| | » | 19. Constructing the crust at the Galapagos Spreading Center
JGR, 2004
| | » | 18. Atlantis core complex
EPSL, 2004
| | » | 17. Morphology of the Galapagos Spreading Center
G-cubed, 2003
| | » | 16. Crustal structure of the East Pacific Rise
GJI, 2003
| | » | 15. Plume-ridge interaction along the Galapagos Spreading Center
G-cubed, 2002
| | » | 14. Compensation of the Galapagos swellEPSL, 2002
| | » | 13. Structure of Tenerife, Canary Islands
JVGR, 2000
| | » | 12. Underplating in the Canary Islands
JVGR, 2000
| | » | 11. Structure of the Mid-Atlantic Ridge (MARK, 23?20'N)
JGR, 2000
| | » | 10. Structure of the Mid-Atlantic Ridge (35?N)
JGR, 2000
| | » | 9. Structure of Gran Canaria, Canary Islands
J. Geodyn., 1999
| | » | 8. Structure of overlapping spreading centers in the MELT area
GRL, 1998
| | » | 7. Crustal thickness in the MELT area
Science, 1998
| | » | 6. The MELT experiment
Science, 1998
| | » | 5. The Canary Islands swell
GJI, 1998
| | » | 4. Morphology of the Galapagos Spreading Center
JGR, 1997
| | » | 3. Faulting of slow-spreading oceanic crust
Geology, 1997
| | » | 2. Flexure beneath Tenerife, Canary Islands
EPSL, 1997
| | » | 1. Elastic thickness in the Canary Islands
GRL, 1994
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Canales, J. Pablo, Satish C. Singh, Robert S. Detrick, Suzanne M. Carbotte, Alistair Harding, Graham M. Kent, John B. Diebold, Jeffrey Babcock, and Mladen R. Nedimovic , Seismic Evidence for Variations in Axial Magma Chamber Properties Along the Southern Juan de Fuca Ridge, Earth Planet. Sci. Lett., 246, 353-366, 2006
Abstract
Multichannel seismic data collected along the Cleft segment on the southern Juan de Fuca Ridge shows that this intermediate-spreading center is underlain by a mid-crustal reflector interpreted as the top of an axial magma chamber (AMC). The AMC reflection is present along most of the segment, and deepens gently from 2.0 km near the southern end of the segment beneath the RIDGE Cleft Observatory Site, to 2.3 km at the northern end beneath the site of the mid-1980’s submarine eruption. We analyzed the one-dimensional seismic structure of the AMC at two locations with contrasting lava chemistry beneath two different hydrothermal vent fields. At the northern site, waveform modeling in the time intercept-slowness (τ-p) domain indicates that the AMC is ~100 m thick and it is characterized by a decrease in P-wave velocity from 6 km/s to 3.7 km/s. In contrast, the P-wave velocity within the shallower, ~100-m-thick AMC at the southern site is higher (5.0 km/s). The decrease in seismic velocity within the AMC indicates that it is partially molten, and that it is not a cracking front as previously suggested for other intermediate-spreading segments. The data show a coherent seismic phase interpreted as the P- to S-wave conversion at the AMC (PAMCS). Stacking of this event shows that the PAMCS is only present along the northern part of the segment. Our results thus suggest along-axis variations in the crystallinity of the AMC. The AMC along Cleft varies from a high crystal content (<30% melt) sill at the southern end of Cleft, to a largely melt (60-75%) sill at the source of the 1980’s eruption at the northern end. The variations in magma chamber properties inferred from our seismic data correlate with changes in lava chemistry and with the location of hydrothermal plumes, and they all suggest that focused, high-temperature hydrothermal venting along intermediate-spreading ridges is closely linked to the physical state of the underlying magma chamber.
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