Study of the Lower Crust and Upper Mantle Using Ocean Bottom Seismographs

  1. Robert F. Mereu,
  2. Stephan Mueller and
  3. David M. Fountain
  1. Yuri P. Neprochnov

Published Online: 9 APR 2013

DOI: 10.1029/GM051p0159

Properties and Processes of Earth's Lower Crust

Properties and Processes of Earth's Lower Crust

How to Cite

Neprochnov, Y. P. (1989) Study of the Lower Crust and Upper Mantle Using Ocean Bottom Seismographs, in Properties and Processes of Earth's Lower Crust (eds R. F. Mereu, S. Mueller and D. M. Fountain), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM051p0159

Author Information

  1. Shirshov Institute of Oceanology, Ussr Academy of Sciences, Moscow 117218

Publication History

  1. Published Online: 9 APR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875904566

Online ISBN: 9781118666388

SEARCH

Keywords:

  • Earth—Crust—Congresses;
  • Geophysics—Congresses

Summary

The bulk of seismic data obtained by the Shirshov Institute of Oceanology during ocean bottom seismograph experiments, as well as other published determinations of seismic structure of the lower oceanic crust and upper mantle are examined. A review of these data indicates: (1) the presence of layer 3B (velocity 7.4 km/s) under the Shatsky and Hess Rises, whereas a small quantity of sites (10%) in the Pacific Ocean basin shows layer 3B; (2) the absence of layer 3A in the studied area of the Brazil basin; (3) the lateral variation of the crustal structure in the central Indian Ocean basin correlated to the intraplate deformation. Statistical analyses of results from over 650 sites show a smaller layer 3 thickness in the Indian Ocean basin (3.8 km) than in the basins of the Pacific Ocean (4.7 km). An essential age dependence, revealing a cyclic pattern, has been defined and statistically validated for the seismic parameters of the crust in the Eastern Pacific Ocean basin. the variations In the crustal structure are in good agreement with the global tectonic cycles, particularly with variations of sea-floor spreading. the petrology of seismic layers of the crust sampled by dredging in fracture zones is also presented.