TY  - JOUR
AU  - Houser C, Masters G.
PY  - 2008//
TI  - Shear and compressional velocity models of the mantle from cluster analysis of long-period waveforms
JO  - Geophysical Journal International
SP  - 195
EP  - 212
VL  - 174
IS  - 1
PB  - Blackwell Publishing Ltd
KW  - Mantle processes
KW  - Body waves
KW  - Seismic tomography
KW  -
N2  - We present a new technique for the efficient measurement of the traveltimes of long period body wave phases. The technique is based on the fact that all arrivals of a particular seismic phase are remarkably similar in shape for a single event. This allows the application of cross-correlation techniques that are usually used in a regional context to measure precise global differential times. The analysis is enhanced by the inclusion of a clustering algorithm that automatically clusters waveforms by their degree of similarity. This allows the algorithm to discriminate against unusual or distorted waveforms and makes for an extremely efficient measurement technique. This technique can be applied to any seismic phase that is observed over a reasonably large distance range. Here, we present the results of applying the algorithm to the long-period channels of all data archived at the IRIS DMC from 1976 to 2005 for the seismic phases S and P (from 23° to 100°) and SS and PP (from 50° to 170°). The resulting large data sets are inverted along with existing surface wave and updated differential traveltime measurements for new mantle models of S and P velocity. The resolution of the new model is enhanced, particularly, in the mid-mantle where SS and PP turn. We find that slow anomalies in the central Pacific and Africa extend from the coremantle boundary to the upper mantle, but their direct connection to surface hotspots is beyond our resolution. Furthermore, we find that fast anomalies that are likely associated with subducting slabs disappear between 1700 and 2500 km, and thus are not continuous features from the upper to lower mantle despite our extensive coverage and high resolution of the mid-mantle.
SN  - 1365-246X
UR  - http://dx.doi.org/10.1111/j.1365-246X.2008.03763.x
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=2812), last updated on Fri, 05 Jul 2024 22:10:02 +0200
ID  - HouserC2008
ER  -