Geophysical imaging of the deep seated pluming system feeding and controlling the Logatchev Hydrothermal vent field at the Mid-Atlantic Ridge near 15°N

• Applicants: Professor Dr. Torsten Dahm; Professor Dr. Ingo Grevemeyer; Dr. Marion Jegen-Kulcsar
• Subject Area: Geophysics
• Term: from 2007 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 53326628

• Final Report Year: 2011

Final Report Abstract

The results of this project show that seafloor compliance measurements using an STS2 broadband sensor are possible. Seafloor compliance analysis using DEPAS stations are not optimal, but may be used at frequencies above 0.01Hz. Infragravity waves (IGW) with sufficient energy could be observed at the Mid Atlantic Ridge but also in the Aegean Sea. Shear wave velocity models could be derived, but resolution is not very large. The data collected at the Logatchev hydrothermal field were not sufficient to draw sound conclusions on the existence of possible melt lenses at mid-crustal depth, although we could not find any such indications. However, the deployements across the Terceira Rift off shore Sao Miguel (Azores) indicate a clear compliance anomaly, which we interpret as a result of the partial melting at the ridge axis. We used a 1D and 2D modelling approach to constrain the width, depth and strength of the anomaly.

Publications

• EMSEIS Project: Planning seafloor compliance measurements in the Mid Atlantic Ridge (MAR). SPP1144 workshop. Etelsen. 2008
  Rios, C., T. Dahm, M. Jegen
  
• Seafloor compliance estimations in the Aegean Sea, Greece. 31st General Assembly of the European Seismological Commission. Crete (Greece). 2008
  Rios, C., T. Dahm, W. Friederich
  
• Seafloor compliance estimations in the Aegean Sea, Greece. 68. Jahrestagung der Deutschen Geophysikalischen Gesellschaft. Freiberg. 2008
  Rios, C., T. Dahm, W. Friederich
  
• Scientific Cruise report Poseidon P381 DAHM. 2009
  
  
• Development of the new very broadband compliance ocean bottom station. European Geosciences Union General Assembly. Austria (Vienna). 2010
  Rios, C., T. Dahm, J. Buelow, S. Winter
  
• Using pressure and seismological broadband ocean data to model shear wave velocities in the north Atlantic. European Geosciences Union General Assembly. Austria (Vienna). 2010
  Rios, C., T. Dahm, M. Jegen