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No. 49: Jan-Feb 1987

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Moho Vicissitudes

For a long time the Moho (Mohorovicic discontinuity) has been considered a stable plane dividing the crust from the mantle. It is at the Moho that seismic wave velocities change abruptly. There is something there, but no one knows just what. At the recent Second International Symposium on Deep Seismic Reflection Profiling of the Continental Lithosphere, a lot of doubts about the stability and character of the Moho surfaced. Under the North American Cordillera, which runs from Alaska to Mexico, the Moho is flat, continuous and oblivious to the faults, terrane plastering, mountain "roots," and the geological phenomena above it. In other areas, though, several Mohos are stacked up. Some Mohos are discontinuous, jumping from one depth to another. Others are strongly influenced by overhead geological structures. Gone is the neat, so simple Moho figured in all the textbooks.

(Barton, Penny; "Deep Reflections on the Moho," Nature, 323:392, 1986. Also: Weisburd, S.; "The Moho Is Immutable No More," Science News, 130:326, 1986.)

From Science Frontiers #49, JAN-FEB 1987. 1987-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987