HR: 14:10h
AN: S33D-03    [Abstracts]
TI: A comparison of plume images in P- and S-wave tomography
AU: Montelli, R
EM: montelli@princeton.edu
AF: Princeton University, Dept. Geosciences, Princeton, NJ 08544 United States
AU: * Nolet, G
EM: nolet@princeton.edu
AF: Princeton University, Dept. Geosciences, Princeton, NJ 08544 United States
AU: Dahlen, T
EM: fad@princeton.edu
AF: Princeton University, Dept. Geosciences, Princeton, NJ 08544 United States
AU: Masters, G
EM: guy@mahi.ucsd.edu
AF: Scripps Inst. of Oceanography, IGPP, MC0225, La Jolla, CA 92093 United States
AB: We present the results of a global, finite-frequency, tomography experiment using long period S,SS and ScS data. The images of S-wave velocity confirm the existence of deep mantle plumes imaged earlier using P-wave tomography (Montelli et al., Science 2004). We have updated the P wave model using improved crustal corrections and compare the two models. Deep mantle plumes are present beneath Ascension, Azores, Canary, Cape Verde, Cook Island, Crozet, Easter, Kerguelen, Hawaii, Samoa and Tahiti, while Afar, Atlantic Ridge, Bouvet(Shona), Cocos/Keeling, Louisville and Reunion are shown to originate at least below the upper mantle if not much deeper. Plumes that reach only to mid-mantle are present beneath Bowie, Hainan, Eastern Australia and Juan Fernandez; these plumes may have tails too thin to observe in the lowermost mantle, but in either case the images are consistent with an interpretation as dying plumes that have exhausted their source region. In the tomographic images only Eifel, and Seychelles are confined to the upper mantle. Starting plumes are visible in the lowermost mantle beneath South of Java, East of Solomon and in the Coral Sea. All imaged plumes are wide an fail to show plumeheads, suggesting a very weak temperature dependence viscosity for lower mantle minerals, and/or compositional variations. The S-wave velocity images show several minor differences with respect to the earlier P-wave results including plume conduits that extend down to the core-mantle boundary beneath Cape Verde, Cook Island and Kerguelen. A more substantial disagreement between P- and S-wave images reopens the question on the depth extent of the Iceland plume. We suggest that a pulsating behaviour of the plume may explain the variability of the images.
DE: 7203 Body waves
SC: Seismology [S]
MN: Fall Meeting 2005