25.01.2015 Views

IASPEI - Picture Gallery

IASPEI - Picture Gallery

IASPEI - Picture Gallery

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy<br />

(S) - <strong>IASPEI</strong> - International Association of Seismology and Physics of the Earth's<br />

Interior<br />

JSS013 Poster presentation 2244<br />

Temperature estimates of the lithosphere on the romanian territory<br />

constrained by seismic velocity data<br />

Dr. Maria Tumanian<br />

Natural Fields Institute of Geodynamics, Bucharest, Romania <strong>IASPEI</strong><br />

Complex architecture of the lithosphere beneath the Romanian territory is interpreted as a direct result<br />

of the compressive tectonic interaction of three major tectonic compartments (East European Platform,<br />

Moesian Platform, Tisza-Dacia Alpaca terranes) during mountain building in the Carpathian Arc. The<br />

process of the Carpathian orogeny is considered the prevailing factor affecting the deep structure of the<br />

lithosphere, with major consequences on the seismic and magmatic activities. Geological, geophysical<br />

and seismological information collected during the last years indicated complicated thermo-mechanical<br />

structures of the crust and lithosphere and various seismic velocity-depth distributions for each of the<br />

mentioned tectonic units, especially at the plate margins contact. Temperature is a key physical<br />

parameter controlling the crustal and mantle dynamics. In the previous studies the thermal structure of<br />

the three tectonic units has been obtained indirectly through the extrapolation of the heat flow<br />

observations and by thermal modelling simulating the main geodynamic processes affecting the study<br />

area. During the intense processes - oceanic subduction, thickening-type compressive deformations,<br />

volcanic processes and surface geological processes (sedimentation and erosion in sedimentary basins,<br />

overthrusting and erosion in orogenic areas) - the entire lithosphere or parts of it have been involved.<br />

The previous evaluations of the lithosphere temperature required realistic estimates on crustal structure<br />

and distribution of the thermal parameters within the lithosphere. This study proposes a tool to better<br />

evaluate the spatial distribution of the thermal parameters and structures used in thermal modelling<br />

using information supplied by tomographic and seismic refraction experiments (CALIXTO99, Vrancea99<br />

and Vrancea2001). Characteristics of the seismic wave propagation, strongly controlled by the thermal<br />

and mechanical properties of the rocks travelled across, provide an image of the heterogeneous nature<br />

of the lithosphere. A set of shear-wave velocity models determinated by non-linear inversion of the<br />

surface wave velocity data are used in reducing the uncertainties in temperature estimates and to<br />

obtain a refinement of the temperature distribution in the lithosphere beneath the investigated tectonic<br />

units. The technique allows an analysis of the temperature effects in producing velocity variations and<br />

uses the thermally dominated seismic structure, in conjunction with surface heat flow observation, as an<br />

additional constraint on estimates of temperatures.<br />

Keywords: temperature estimates, seismic velocity

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!