Upper Oceanic Crustal Structure

Full waveform inversion was performed on 2-ship, wide-aperture multi-channel seismic reflection data collected along the southern East Pacific Rise. The analysis revealed and exploited converted shear waves not previously seen in the data. The Poisson Ratio structure obtained from the inversion gives insight into the porosity and crack distribution from the seabed, through the extruded pillow basalts and into the sheeted dykes that overlye the magma chamber. These results have important implications for the lithostratigraphy of young oceanic crust and hydrothermal circulation.

Seismic structure of oceanic crustSeismic structure of the upper crust at the East Pacific Rise ridge axis at 14S

(From Collier & Singh, 1998)

This research was completed under the BRIDGE programme of NERC


  • "Poisson´s ratio structure of young oceanic crust" (1998) J S Collier, S.C. Singh.  J. Geophys. Res., Vol.103, No.B9, pp.20981-20996 PDF
  • "Seismic evidence for a hydrothermal layer above the solid roof of the axial magma chamber" (1999) S.C. Singh, J S Collier, A.J. Harding, G.M. Kent, J.A. Orcutt.  Geology, Vol.27, No.3, pp.219-222  PDF

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