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| Titel |
The upper mantle transition zone beneath the Ibero-Maghrebian region as seen by teleseismic Pds phases |
| VerfasserIn |
Luciana Bonatto, Martin Schimmel, Josep Gallart, José Morales |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091970
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| Publikation (Nr.) |
 EGU/EGU2014-6290.pdf |
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| Zusammenfassung |
| We analyze the upper-mantle transition zone discontinuities at a depth of 410 km and 660 km
as seen from seismic P -to-s wave conversions beneath the Ibero-Maghrebian region. For this
purpose, we use teleseismic events recorded at 259 broadband seismic stations deployed
mainly by the TopoIberia project. The detailed analysis of the transition-zone discontinuities
provides information on the temperature and composition of the upper mantle at the
investigated depths.
The converted waves from the upper-mantle discontinuities arrive in the P-wave coda
together with other signals and are usually identified on stacked receiver functions. Here, a
new processing approach is built, which is leaned on receiver functions and which is based on
cross-correlation and stacking techniques, to efficiently detect and extract signals by means of
their coherence, slowness, travel time and polarity. In order to add consistency and robustness
to the detections, our final results are based on a joint analysis of the receiver functions and
two different cross-correlation functionals. This permits to assess errors and to
bridge observation gaps due to detection failure of any of the techniques inherent
to signal and noise characteristics. Finally, discontinuity depths are determined
using time corrections obtained from a 3D velocity model. We present topography
maps for the 410-km and 660-km discontinuities, which show variations in the
transition zone thickness beneath the study area. The results are discussed to add
new constraints on temperature and composition to seismic velocity anomalies
observed in the transition zone beneath the controversial Ibero-Magrhrebian region. |
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