Structure of the Folded Areas and Recent Geosynclines of the Okhotsk Area

  1. Leon Knopoff,
  2. Charles L. Drake and
  3. Pembroke J. Hart
  1. I. K. Tuyezov,
  2. P. M. Sichev,
  3. R. Z. Tarakanov and
  4. M. L. Krasny

Published Online: 18 MAR 2013

DOI: 10.1029/GM012p0473

The Crust and Upper Mantle of the Pacific Area

The Crust and Upper Mantle of the Pacific Area

How to Cite

Tuyezov, I. K., Sichev, P. M., Tarakanov, R. Z. and Krasny, M. L. (2012) Structure of the Folded Areas and Recent Geosynclines of the Okhotsk Area, in The Crust and Upper Mantle of the Pacific Area (eds L. Knopoff, C. L. Drake and P. J. Hart), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM012p0473

Author Information

  1. Sakhalin Complex Scientific Research Institute, Novo-Alexandrovsk, Sakhalin, USSR

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 20 APR 2012

Book Series:

  1. Geophysical Monograph Series

Book Series Editors:

  1. Waldo E. Smith

ISBN Information

Print ISBN: 9780875900124

Online ISBN: 9781118663738

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Keywords:

  • Focal zone;
  • Folded areas;
  • Geosynclines;
  • Granitic layer;
  • Kuril-Kamchatka geosyncline;
  • Okhotsk area;
  • Suboceanic crust

Summary

The folded regions of the Okhotsk area—Primor'e, Sakhalin, Okhotsk, west Kamchatka—differ in structure, composition, physical state, and seismicity of the crust and upper mantle from the recent Kuril-Kamchatka geosyncline (south Okhotian and Kuril-Kamchatka trenches, Kuril arc, and east Kamchatka). The crust of the folded area is mainly continental; magnetic disturbances are located primarily in the ‘granitic’ layer, and the region is generally isostatically compensated. The energy of seismic activity is lower than in the geosyncline area; earthquakes occur in the crust and also in the well known inclined focal zone at great depth (more than 300 km). These deep earthquakes probably have no influence on the formation and development of near-surface structures. The geosyncline region is characterized by a variety of magnetically disturbing bodies; substantial density inhomogeneities (0.1 g/cc in the crust under the Yuzhno-Okhotsk depression and in the crust and mantle under the Kuril archipelago; 0.2 g/cc in the mantle under a 100-km-wide band at the west slope of the Kuril-Kamchatka trench); sharp changes in velocity of seismic waves; and high temperatures, zones of magma generation, and recent volcanic activity in the Kuril-Kamchatka arc.