HR: 0830h
AN: S41D-0112    [PDF]
TI: Seismic attenuation and electrical resistivity beneath the southern Altiplano plateau
AU: Haberland, C
EM: haber@geo.uni-potsdam.de
AF: University of Potsdam, Institute of Geosciences, PO Box 60 15 53, Potsdam, 14415 Germany
AU: * Rietbrock, A
EM: A.Rietbrock@liv.ac.uk
AF: University of Liverpool, Department of Earth & Ocean Sciences, 4 Brownlow Street, Liverpool, L69 3GP United Kingdom
AU: Schurr, B
EM: bernd.schurr@ctbto.org
AF: CTBTO, IDC/Scientific Methods, Wagramerstr. 5, Vienna, A-1400 Austria
AU: Brasse, H
EM: h.brasse@geophysik.fu-berlin.de
AF: Free University of Berlin, FR Geophysics, Malteserstr. 64-100, Berlin, 12249 Germany
AB: The analysis of local earthquake data from the temporary seismological ANCORP network allowed the calculation of 3D attenuation ($Q_p$) tomographic images of crust and upper mantle beneath the southern Bolivian Altiplano around 21\deg~S. The tomographic images show a low-$Q_p$ middle and lower crust and a moderate-$Q_p$ upper mantle beneath the southern Altiplano. Beneath the recent magmatic arc, $Q_p$ is not significantly decreased at this latitude. The continental forearc and the downgoing Nazca plate generally show high $Q_p$. The distribution of crustal $Q_p$ coincides with the variation of electrical resistivity, which limits the possible mechanisms causing the anomalies. Our results support the hypothesis that partial melts in middle and lower crust beneath the Altiplano are present on a large scale. We see no evidence for a shallow asthenosphere beneath the southern Altiplano.
DE: 5109 Magnetic and electrical properties
DE: 7203 Body wave propagation
DE: 7218 Lithosphere and upper mantle
DE: 8102 Continental contractional orogenic belts
DE: 8180 Tomography
SC: Seismology [S]
MN: 2003 Fall Meeting