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

• Main Authors: Smithson, Scott B., Schatzman, James C.
• Other Authors: WYOMING UNIV LARAMIE DEPT OF GEOLOGY
• Format: Text
• Language: English
• Published: 1997
• Subjects: Geology; Geochemistry and Mineralogy; *EARTH MANTLE; *COMPRESSION WAVES; USSR; TWO DIMENSIONAL; EARTH CRUST; TOMOGRAPHY; SEISMIC VELOCITY; TRAVEL TIME; *VELOCITY MODELS; DSS(DEEP SEISMIC SOUNDING); Barents Sea; Kola Peninsula; kola peninsula
• Online Access: http://www.dtic.mil/docs/citations/ADA329400; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA329400

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.