Accession Number : AD0628163

Title :   SEISMIC STUDY OF CRUSTAL STRUCTURE IN THE SOUTHERN ROCKY MOUNTAINS.

Descriptive Note : Technical Letter Crustal Studies,

Corporate Author : GEOLOGICAL SURVEY DENVER COLO

Personal Author(s) : Jackson,W. H. ; Pakiser,L. C.

Report Date : 26 JAN 1966

Pagination or Media Count : 9

Abstract : Two underground mining blasts of 25,500 pounds and 416,235 pounds of explosives, detonated at Climax, Colo., on May 21 and 23, 1964, were recorded at 17 locations in the Front Range uplift of the Southern Rocky Mountains at distances ranging from 25 to 360 km north of the shotpoint. Strong secondary events recorded at distances ranging from 119 to 192 km from the shotpoint were identified as reflections from the Mohorovicic discontinuity and from an intermediate layer in the crust. An analysis of both reflected and refracted events suggests that the crustal thickness north of Climax is approximately 54 km and that it decreases abruptly by about 15 km in the area directly east of the Uinta Mountains. Comparison of crustal models in the different geologic and physiographic provinces of the Far West indicates that isostatic compensation is related primarily to density variations in the upper mantle and only secondarily to variations in crustal thickness. (Author)

Descriptors :   (*SEISMOLOGY, COLORADO), (*MOUNTAINS, COLORADO), (*GEOLOGY, COLORADO), UNDERGROUND EXPLOSIONS, SEISMIC WAVES, PROPAGATION, GEOPHYSICAL PROSPECTING, WYOMING, UTAH

Subject Categories : Geology, Geochemistry and Mineralogy
      Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE