Article Vol. 21, No. 1, p. 4754, February 2017 http://dx.doi.org/10.1007/s12303-016-0036-7 pISSN 1226-4806 eISSN 1598-7477 Geosciences Journal GJ The sub-crustal stress estimation in central Eurasia from gravity, terrain and crustal structure models Robert Tenzer 1,2 * , Mehdi Eshagh 3 , and Wenbin Shen 1 1 The Key Laboratory of Geospace Environment and Geodesy, School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China 2 New Technologies for the Information Society (NTIS), University of West Bohemia, 306 14, Plzen, Czech Republic 3 Department of Engineering Science, University West, S-461 32, Trollhättan, Sweden ABSTRACT: We investigate the horizontal stress field beneath crustal structures of central Eurasia. The numerical procedure applied for a simultaneous determination of the sub-crustal stress and the crustal thickness from the global gravity, terrain and crustal structure models is based on solving Navier-Stokes’ problem which incorporates the inverse solution to the Vening Meinesz- Moritz’s problem of isostasy. The numerical results reveal that a spatial distribution of the sub-crustal stress in this study area closely resembles the regional tectonic configuration comprising parts of the Eurasian, Indian and Arabian lithospheric plates. The maximum shear stress intensity is generated by a subduction of the Indian plate beneath the Tibetan block. The intra-plate tectonic configuration is marked by the stress anomalies distributed along major active strike-slip fault systems and sections of subduction which separate the Tibetan and Iranian blocks from the rest of the Eurasian plate. The most pronounced intra-plate stress anomalies are related with a subduction of the Eurasian plate beneath the Tibetan block. We also demonstrate that a prevailing convergent orientation of stress vectors agree with the compressional tectonism of orogenic formations (Himalaya and Tibet Plateau, Than Shan, Zargos and Iranian Plateau), while the extensional tectonism of continental basins (Tarim, Ganges-Brahmaputra, Sichuan) is manifested by a divergence of stress vectors. Key words: crust, gravity, Moho, stress field, Tibet Manuscript received March 30, 2015; Manuscript accepted June 6, 2016 1. INTRODUCTION The earthquake focal mechanisms, well bore breakouts and drilling-induced fractures, in situ stress measurements (i.e., overcoring, hydraulic fracturing, borehole slotter) and young geologic data (from fault-slip analysis and volcanic vent alignments) are main sources of information used to investigate the near- surface tectonic stresses. These data were used, for instance, to compile the World Stress Map database. The overview of applied methodologies can be found Zoback et al. (1989), Zoback and Zoback (1980, 1991) and Sperner et al. (2003). To investigate the stress field at greater depths different data types are required. Most of the Earth’s lithospheric stress is induced by mantle convection and to some extent also by a crustal load of isostatically uncompensated topographic features and heterogeneous lithospheric density structures. To investigate the sub-crustal stress induced by mantle convection, Runcorn (1964, 1967) formulated a direct relation between stress and gravity. He simplified the Navier-Stokes’ equations to derive horizontal components of the sub-crustal stress based on assuming a two-layered Earth’s model. He then used the low-degree spherical harmonics of the Earth’s gravity field to deduce the global horizontal stress pattern and found a correlation between the convergent and divergent sites established by the plate theory. The sub-crustal stress has been studied also in context of interpreting tectonic and magnetic features, deep earthquake mechanisms, volcanism, subduction, mantle convection, heat flow, kimberlite magmatism and ore concentration (cf. Liu, 1977). Liu (1977, 1978, 1979), for instance, applied the Runcorn’s method to construct maps of the convection-generated stresses driving movements of tectonic plates. Liu (1977) calculated and presented the convection pattern and stress system under *Corresponding author: Robert Tenzer School of Geodesy and Geomatics, The Key Laboratory of Geospace Environment and Geodesy, Wuhan University, 129 Luoyu Road, Wuhan 430079 China Tel: +86 27 6877 8649, Fax: +86 27 6877 1695, E-mail: rtenzer@sgg.whu.edu.cn The Association of Korean Geoscience Societies and Springer 2017