Accession Number:

ADA210241

Title:

Surface Wave Ray Tracing and Ms:Yield Determination in a Laterally Heterogeneous Earth

Descriptive Note:

Final rept. 7 Jan 1987-31 Dec 1988

Corporate Author:

UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF GEOLOGICAL SCIENCES

Report Date:

1989-02-01

Pagination or Media Count:

62.0

Abstract:

Pure path Rayleigh wave group velocities for 24 regional grids inside the Arctic have been obtained from 74 mixed path measurements. The vertical shear wave velocity structures under these 24 grids were then determined according to their pure path group velocity dispersion data. This result indicates that the crustal shear wave velocity in the Arctic region is generally lower than the world-wide average. In addition, a typical mid-ocean ridge structure was clearly shown under the Nansen Ridge. We also found an abnormally high upper mantle shear wave velocity under the Alpha Ridge and Makarov Basin, and low velocity beneath the Canadian Arctic Islands. In general, our inversion result agrees with the known tectonics in the Arctic region. To further check the validity of our result, we computed synthetic Rayleigh waves a comparison with our observations shows very good agreement. Keywords Seismic wave velocity Ocean bottom topography Tectonics Rayleigh wave dispersion Ocean basins Earthquake seismic data Earth crust thickness Upper mantle Structural geology Surface waves Ray tracing Earth models.

Subject Categories:

  • Seismology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE