scholarly journals SKS-wave splitting and upper mantle structure: results in the Southern Apennines

1998 ◽  
Vol 41 (4) ◽  
Author(s):  
L. Margheriti
Keyword(s):  
Upper Mantle ◽  
Seismic Anisotropy ◽  
Mantle Structure ◽  
Southern Apennines ◽  
Mountain Belt ◽  
Upper Mantle Structure ◽  
Delay Times ◽  
Wave Splitting ◽  
Sks Wave ◽  
Splitting Measures

Shear wave splitting measures at six temporary stations in the Southern Apennines are computed analyzing fifteen events recorded during the spring and summer 1996, with magnitude greater than 5.8. The splitting parameters were measured using Silver and Chan's (1991) method only on SKS and SKKS phases. Evidence for strong seismic anisotropy was found at all the stations: delay times dt are generally larger than 1.5 s and fast directions Ø are quite variable in different geodynamic domains. NW-SE Ø average directions are found at stations on the mountain belt while at stations on the foredeep and foreland Ø is on average N-S. Changes in splitting parameters may be related to upper mantle structure, and particularly to the geometry of a fragmented lithosphere subducting beneath the Apennines.

Seismic anisotropy of mantle xenoliths and constraints on upper mantle structure beneath the southern Canadian Cordillera

2001 ◽  
Vol 339 (3-4) ◽  
pp. 403-426 ◽  
Author(s):  
Kazuko Saruwatari ◽  
Shaocheng Ji ◽  
Changxing Long ◽  
Matthew H Salisbury
Keyword(s):  
Upper Mantle ◽  
Seismic Anisotropy ◽  
Mantle Xenoliths ◽  
Canadian Cordillera ◽  
Mantle Structure ◽  
Upper Mantle Structure

scholarly journals Large-scale variation in seismic anisotropy in the crust and upper mantle beneath Anatolia, Turkey

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Cédric P. Legendre ◽  
Li Zhao ◽  
Tai-Lin Tseng
Keyword(s):  
Upper Mantle ◽  
Large Scale ◽  
Seismic Anisotropy ◽  
Crust And Upper Mantle ◽  
Wave Splitting ◽  
Mantle Processes ◽  
Open Question ◽  
Subduction System ◽  
Anisotropic Phase ◽  
Regional Tectonics

AbstractThe average anisotropy beneath Anatolia is very strong and is well constrained by shear-wave splitting measurements. However, the vertical layering of anisotropy and the contribution of each layer to the overall pattern is still an open question. Here, we construct anisotropic phase-velocity maps of fundamental-mode Rayleigh waves for the Anatolia region using ambient noise seismology and records from several regional seismic stations. We find that the anisotropy patterns in the crust, lithosphere and asthenosphere beneath Anatolia have limited amplitudes and are generally consistent with regional tectonics and mantle processes dominated by the collision between Eurasia and Arabia and the Aegean/Anatolian subduction system. The anisotropy of these layers in the crust and upper mantle are, however, not consistent with the strong average anisotropy measured in this area. We therefore suggest that the main contribution to overall anisotropy likely originates from a deep and highly anisotropic region round the mantle transition zone.

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