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| Titel |
Crustal tomography of the Aegean-Anatolian domain using noise cross-correlations |
| VerfasserIn |
Fabien Hubans, Anne Paul, Michel Campillo, Hayrullah Karabulut, Panagiotis Hatzidimitriou |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039865
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| Zusammenfassung |
| Data of more than 150 temporary and permanent broadband seismological stations deployed
in the Aegean-Anatolian domain between May 2007 and May 2009 are grouped in the
SIMBAAD (Seismic Imaging of the Mantle Across the Anatolian Domain) dataset. We
compute noise cross-correlations between all station pairs on a  1.5-yr duration. We obtain
more than 11.000 correlations for each component of the cross-correlation tensor. We apply a
MFA (Multiple Filter Analysis) method to measure group velocity dispersion curves of
Rayleigh waves on 4 components of the correlation tensor (ZZ, ZR, RZ, RR) and of
Love waves on the TT component, both in positive and negative times. According
to the theory, a noise cross-correlation converges to the Green function if noise
sources are randomly distributed around the station pair. If this condition is fulfilled,
the cross-correlation should be symmetrical in time. We compare group velocity
measurements between positive and negative times to evaluate the convergence of each
cross-correlation to the Green function. The quality of the symmetry is used to weight the
time measurements in the inversion for group velocity maps. In the last step, Rayleigh
wave group velocity data are inverted for a 3-D model of S-wave velocity. This
processing gives an image of the crustal structure in the area [37-41°N ; 23-33°E] with a
horizontal resolution of 60 to 200 km depending on depth and station coverage. The
shallowest layers clearly display the present-day thick sedimentary basins (Axios,
Thrace, Marmara, Bay of Antalya, ...) and older sedimentary nappes (Lycian nappes,
Miocene sediments in the Kirsehir block) as strong low velocity anomalies. At larger
depth, Southwestern Anatolia is characterized by a broad low velocity anomaly
which contrasts with the higher velocities of the Aegean Sea. We clearly image
a West to East increase of Moho depth from 20-25 km in the Aegean Sea to 35
km in the Anatolian plateau. This increase located between 27°E and 28°E can be
linked to a lateral change in the amount of North-South extension measured by
GPS.
SIMBAAD Team : T. Afacan (2), M. Aktar (2), K. Bourova-Flin (1), D.M.
Childs (2), L. Dimitrova (4), D. Hatzfeld (1), E. Karagianni (3), I. Karagianni (3), D.
Kementzetzidou (3), A. Komec Mutlu (2), Y. Ozakin (2), C. Papazachos (3), C. Péquegnat
(1), S. Roussel (1), G. Salaün (1), D. Samut (2), M. Scordilis (3), D. Vamvakaris (3) |
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