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| Titel |
Preliminary results from receiver function analysis in a seismological network across the Pamir |
| VerfasserIn |
Felix M. Schneider, Xiaohui Yuan, Christan Sippl, Bernd Schurr, James Mechie, Vlad Minaev, Ilhomjon Oimahmadov, Mustafo Gadoev, Ulan A. Abdybachaev |
| 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 |
250034478
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| Zusammenfassung |
| The multi-disciplinary TIen Shan-PAmir GEodynamic (TIPAGE) program aims to investigate
the dynamics of the orogeny of the Tien Shan and Pamir mountains, which are situated in
south Kyrgyzstan and east Tajikistan in Central Asia. Deformation and uplift accompanied by
crustal thickening is mainly induced by the collision between the Indian and Eurasian
continental plates. As a local feature this collision provides the world’s largest active
intra-continental subduction zone.
Within the framework of the TIPAGE program we operate a temporary seismic array
consisting of 32 broadband and 8 short period seismic stations for a period of two years (from
2008 to 2010) covering an area of 300 x 300 km over the main part of the central Pamir
plateau and the Alai-range of the southern Tien Shan. In the first year 24 broadband stations
were set up in a 350-km long north-south profile geometry from Osh in southern Kyrgyzstan
to Zorkul in south-eastern Tajikistan with approximately 15 km station spacing. We perform a
receiver function (RF) analysis of converted P and S waves from teleseismic earthquakes at
epicentral distances of 35-95 degrees with a minimum magnitude of 5.5. Therefore we
decompose their wavefields by rotating the coordinate systems of the recorded
seismograms from a N,E,Z into a SH,SV,P system. RFs are isolated by deconvolution of
the P-component from the SH- and SV-component. They provide a robust tool to
locate discontinuities in wave velocity like the Moho and thus represent the method
of choice to determine crustal thickness. First results show a crustal thickness of
70-80km. Xenolith findings from depths of 100km reported by Hacker et al. (2005) give
indication for even higher values. The N-S profile geometry will produce a high
resolution RF image to map the gross crustal and lithospheric structure. In addition a 2D
network with additional 16 stations will enable an investigation of lateral structure
variation.
We give an introduction to the project and methodology as well as a presentation of our
preliminary most recent results on crustal thickness and Poisson’s ratio along the profile from
the data of the first year. |
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