Extensive‐Dilatancy Anisotropy (Eda) Inferred From Observations of Crustal Shear Waves Generated By A Refraction Experiment In Northern Scandinavia

Abstract

Summary. Particle‐motion plots of shear waves have been studied for the section FG of the FENNOLORA seismic experiment. Shear‐wave splitting is observed on some records and the polarization of the first arriving shear waves show two peaks at about N35°W and N65°E. These results can be interpreted as being due to crack‐induced anisotropy with the crack direction dominated by a (dominant) horizontal stress around N35°W. This is consistent with in situ stress measurements and focal mechanism studies in Scandinavia. the results show that seismic refraction experiments may be useful in providing evidence of crack‐induced anisotropy in the stable continental crust. Copyright © 1987, Wiley Blackwell. All rights reserved