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| Titel |
Magnetotelluric data analysis from the continental collision zone in the Pamir and Tien Shan, Central Asia |
| VerfasserIn |
Paul Sass, Oliver Ritter, Gerard Muñoz, Anatolii Rybin, Vladislav Batalev |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053355
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| Zusammenfassung |
| A magnetotelluric (MT) dataset was obtained within the multi-disciplinary Tien Shan – Pamir
Geodynamic Program (TIPAGE) along a 340 km long profile from Osh in Kyrgyzstan via
Murghab, Sarytash, the Kyrgyz-Tajik border, Karakul and Murghab to Zorkul in southern
Tajikistan. It probes one of the deepest active intra-continental subduction zones on Earth and
will help to establish how the highest strain over the shortest distance that is manifested in the
India–Asia collision is accommodated structurally. In total there are 178 MT stations,
whereof 26 combine long-period (LMT) and broad band (BB) recordings, with a frequency
range of 10-4 - 10-1 Hz and 10-3 - 103 Hz, respectively. A typical spacing was
approximately 2 km between BB-only sites and 14 km for the combined BB and LMT
sites.
We present and discuss preliminary 2D and 3D modelling results. The geoelectric strike
directions are consistent with the predominant geological strike, roughly in E-W directions. A
dimensionality evaluation of the data reveals the influence of off-profile features. Taking into
account the profile geometry we attempt a combination of 2D and 3D inversion
techniques. Robust subsurface resistivity features are a generally resistive upper crust in
the Pamir region and several zones of high conductivity at lower crustal levels,
particularly below the Pamir plateau. Zones of high electrical conductivity often imply the
presence of fluids and may represent mechanically weaker areas which can absorb
accommodated strain. The observed resistivity values and the depth range are similar to
conductors below the Tibetan plateau which were interpreted as zones of lower crustal
flow. |
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