Accession Number : ADA329400

Title :   Analysis of Soviet DSS Records for Propagation and Modeling of Lg Blockage across Major Crustal Features

Descriptive Note : Final technical rept. 15 Oct 93-14 Oct 96

Corporate Author : WYOMING UNIV LARAMIE DEPT OF GEOLOGY

Personal Author(s) : Smithson, Scott B. ; Schatzman, James C.

PDF Url : ADA329400

Report Date : 04 APR 1997

Pagination or Media Count : 46

Abstract : To develop our model, we analyze the data obtained using 42 chemical explosions along the profile. Applying a travel-time tomographic inversion method, we developed a velocity model and estimates of its resolution. Two important resolved features of the model are: 1) high velocity block at the base of the crust under the Baltic Shield, 2) crustal roots under the Ural Mountains. Using the data from 3 nuclear explosions in the profile we developed a 2-D upper mantle P-wave velocity model. The model supports the conclusion of the roots under the Urals, and suggests a southeast dipping interface at about 80 km in the upper mantle. A high-frequency phase following teleseismic Pn from the PNEs is interpreted as a "whispering-gallery" phase and is used to estimate attenuation within the upper mantle. Lg from 2 PNEs is blocked between sedimentary basins and the Ural Mountains. A marine-land profile recorded from the Barents Sea to the Kola Peninsula shows a crustal thickness of about 38-40 km at the coast.

Descriptors :   *EARTH MANTLE, *COMPRESSION WAVES, USSR, TWO DIMENSIONAL, EARTH CRUST, TOMOGRAPHY, SEISMIC VELOCITY, TRAVEL TIME.

Subject Categories : Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE