A lower mantle S-wave triplication and the shear velocity structure of D''
نویسندگان
چکیده
منابع مشابه
Spectra of mantle shear wave velocity structure
We applied the stochastic method of Gudmundsson, Davies & Clayton (1990) (which was applied to ISC P-wave data) to teleseismic ISC S-wave data to obtain an independent estimate of mantle structure. We inverted the variance of S-wave traveltime residuals of bundles of rays to obtain a description of the spectrum of lateral heterogeneity as a function of depth through the mantle. The technique yi...
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SH signals recorded by an array of four broadband (Benioff 1-90) instruments, run by Caltech, are inspected for evidence of a lower mantle shear wave velocity discontinuity previously detected using WWSSN data. Deep focus earthquakes beneath Argentina span the distance range 78 ø to 82 ø from the array, where the triplication in the travel time curve produced by the discontinuity is expected to...
متن کاملMantle shear-wave velocity structure beneath the Hawaiian hot spot.
Defining the mantle structure that lies beneath hot spots is important for revealing their depth of origin. Three-dimensional images of shear-wave velocity beneath the Hawaiian Islands, obtained from a network of sea-floor and land seismometers, show an upper-mantle low-velocity anomaly that is elongated in the direction of the island chain and surrounded by a parabola-shaped high-velocity anom...
متن کاملA Shear Velocity Discontinuity in the Lower Mantle
A lower mantle S-wave triplication is detected using shortand long-period SH seismograms in the distance range 70 ø to 95 ø . Modeling of the observations with synthetic seismograms indicates that the tripliGation 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 ragion...
متن کاملEVIDENCE OF A LOWER MANTLE SHEAR VELOCITY DISCONTINUITY IN S AND sS PHASES
Teleseismic recordings of direct S and sS body wave phases, and their core-reflected counterparts ScS and sScS, from intermediate and deep focus earthquakes are used to analyze the lowermost mantle shear velocity structure beneath Alaska. A model with a 2.75 % shear velocity increase 280 km above the core-mantle boundary accurately matches waveform complexities in both the S and sS wavetrains. ...
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ژورنال
عنوان ژورنال: Geophysical Journal International
سال: 1983
ISSN: 0956-540X,1365-246X
DOI: 10.1111/j.1365-246x.1983.tb05010.x