Woods Hole Oceanographic Institution

Juan Pablo Canales

»50. EPR Multi-sill plumbing system
Nature Geoscience, 2014

»49. Galapagos Spreading Center: Tomography
AGU Monograph, 2014

»48. Axial Volcano
Geology, 2014

»47. Melt-Mush along the EPR
JGR, 2014

»46. EPR Moho in 3D
G-cubed, 2014

»45. Melt bodies off the EPR
EPSL, 2014

»44. EPR Magma segmentation
Nature Geoscience, 2013

»43. TAG 3D P-wave velocity
G-cubed, 2012

»42. Atlantis core complex
G-cubed, 2012

»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 swell
EPSL, 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

Zhao, M., J.P. Canales, and R.A. Sohn, Three-dimensional seismic structure of a Mid-Atlantic Ridge segment characterized by active detachment faulting (Trans-Atlantic Geotraverse, Mid-Atlantic Ridge 25°55’N-26°20’N), Geochem., Geophys., Geosyst., 13, Q0AG13, 2012

We use air gun shots recorded by ocean bottom seismometers (OBSs) to generate a three-dimensional (3D) P-wave tomographic velocity model of the Trans-Atlantic Geotraverse (TAG) segment of the Mid-Atlantic Ridge, and to search for evidence of reflections from a shallow crustal fault interface. Near-vertical reflections were observed in some of the seismic records from OBSs deployed within the active seismicity zone defined by microearthquake hypocenters. Forward modeling of synthetic seismograms indicates that these reflections are consistent with a fault interface dipping at a low angle toward the ridge axis. Our observations suggest that the fault zone may extend beneath the volcanic blocks forming the eastern valley wall. Our 3D tomographic results show that the across-axis structural asymmetry associated with detachment faulting extends at least 15 km to the east of the ridge axis, indicating that detachment faulting and uplifting of deep lithologies has been occurring at the TAG segment for at least the last ~1.35 Myr. The velocity model contains a 5 km by 8 km velocity anomaly within the detachment footwall. This anomaly, which is present beneath the active TAG hydrothermal mound, is characterized by a velocity inversion at 1.5–2.0 km below seafloor underlain by reduced P-wave velocities (~6.2–6.5 km/s compared to surrounding areas ~7.0–7.2 km/s) extending down to 3.5 km below seafloor. The velocity anomaly likely results from some combination of thermal and/or hydrothermal processes, and in either case our results suggest that hydrothermal fluids circulate within the upper section of the detachment footwall beneath the active mound.


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