Evolution of descending lithospheric slabs as inferred from assimilation of geophysical, geodetic and geological data

• Applicant: Dr. Alik Ismail-Zadeh
• Subject Area: Geophysics
• Term: from 2009 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 84866599

The proposed research is focused on a challenging problem: How to assimilate geophysical, geodetic and geological data in models of mantle-lithosphere dynamics? The fundamental scientific goal of the project proposal is to better understand the evolution of descending lithosphere in two geological domains: the Carpathian collision zone and the Pacific-Philippine Sea subduction zone. Common features of the domains are a descending slab beneath the regions, tectonic stress generation and its release in devastating earthquakes. The domains are distinguished by the style of the lithospheric descent: active subduction of beneath the Japanese island arc (JIS) and gravitational sinking of the Vrancea slab in the SE-Carpathians (SEC). The scientific goal will be achieved by using vast regional geophysical, geological and geodetic data and by employing a new quantitative methodology for data assimilation. The specific objectives of the proposal are (i) to develop a three-dimensional (3-D) data assimilation code for parallel computers permitting non-linear rheology and phase transformations in the mantle; (ii) to develop 3-D models of the present thermal structure beneath the SEC and JIS on the basis of temperatures derived from recent models of seismic tomography and of heat flow in the region; (iii) to develop 3-D numerical models of the evolution of the lithospheric slabs descending beneath the SEC since the Miocene times and beneath the JIS since the Neogene times based on the most relevant models of present thermal structure, as input conditions for the assimilation problems, and on geological and geodetic data on the regional movements; and (iv) to analyse the thermal and structural evolution of the regions on the basis of the developed numerical models and geological hypothesis. The broader impact of the proposed activity includes (a) better fundamental understanding of interplay between mantle and lithosphere dynamics and associated seismicity; (b) developing a methodology for data assimilation to be used by a geodynamics community; and (b) increasing the arsenal of models for the study of dynamics of mantle and lithosphere, geological disasters included.

• DFG Programme: Research Grants