Shear velocity discontinuity in the lower mantle

Journal Article · Sat Jan 01 00:00:00 EST 1983 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL010i001p00063· OSTI ID:6153146

Lay, T; Helmberger, D V

A lower mantle S-wave triplication is detected using short- and long-period SH seismograms in the distance range 70/sup 0/ to 95/sup 0/. Modeling of the observations with synthetic seismograms indicates that the triplication is produced by a 2.75 +- 0.25% shear velocity increase about 280 km above the core-mantle boundary. The SH data from intermediate and deep focus events for three distinct source region-receiver array combinations show generally consistent travel time and relative amplitude behavior of the triplication. There are small, systematic travel time shifts between the source regions which suggest regional variations in the depth of the discontinuity of up to 40 km.

• Research Organization: Seismological Laboratory, California Institute of Technology, Pasadena, California 91125
• OSTI ID: 6153146
• Journal Information: Geophys. Res. Lett.; (United States), Vol. 10:1
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
EARTH MANTLE
SEISMIC S WAVES
BOUNDARY LAYERS
PHASE VELOCITY
SHEAR
STRATIFICATION
WAVE PROPAGATION
LAYERS
SEISMIC WAVES
VELOCITY
580201* - Geophysics- Seismology & Tectonics- (1980-1989)