Accession Number : AD0649264

Title :   STATION CORRECTIONS AT LASA.

Descriptive Note : Scientific rept., 1 Nov 65-31 Oct 67,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF GEOLOGY AND GEOPHYSICS

Personal Author(s) : Fairborn,John W.

Report Date : 01 JUL 1966

Pagination or Media Count : 26

Abstract : Two types of crustal and/or upper mantle lateral inhomogeneities are postulated; they are dipping layers, which have different seismic velocities, and an upper mantle-crustal model having a linear velocity gradient in the horizontal direction. The P-wave travel time deviations as a function of azimuth angle to the earthquake epicenter are calculated for each model and compared, on the basis of magnitude, with the azimuthally dependent part of station corrections observed at LASA and TESO. In the case of LASA, dipping layers cannot account for the observed station corrections. Horizontal velocity gradients, on the other hand, may account for the observations if the thickness over which the gradient extends is sufficiently large - probably greater than the crustal thickness. (Author)

Descriptors :   (*SEISMOLOGICAL STATIONS, CORRECTIONS), SEISMOMETERS, NUCLEAR EXPLOSIONS, AZIMUTH, LITHOSPHERE, EARTHQUAKES, TIME

Subject Categories : Seismology
      Seismic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE