Saturday , January 16 2021

Maps of tectonic deformation on a pan-European scale from the National Observatory

A scientific team of the National Observatory of Athens (NSA) produced for the first time maps of tectonic deformation on a pan-European scale, as part of the European H2020 EPOS program.

The mapping of tectonic deformation on Earth has great utility for assessing seismic hazard and for monitoring geodynamic changes on the planet's surface. Deformation results from the changes in the elastic lithosphere (i.e., the solid cortex and the upper mantle) caused by the tectonics of the plates.

Such changes relate to the shape of a tectonic plate, the rotations made by the tectonic blocks ("blocks") relative to their vertical, as well as the accumulation of elastic energy. Measurements in these sizes of tectonic deformation have improved significantly over recent years thanks to the use of satellite technologies, and in particular the Global Navigation Satellite System (GNSS).

The NCA team, led by Dr. Athanasios Ganas, research director at the Geodynamic Institute, used tectonics from 452 GNSS permanent stations, previously developed by a team of researchers at the French University of Grenoble. Using open source software, Greek scientists have been calculating various parameters. The basic unit of tectonic deformation is one ns / yr (nanostrain / year), which represents the annual change of one millimeter between two points spaced 1 000 km apart.

It was found that in large areas of the Eurasian plate, where seismicity is sparse to nonexistent (eg Northern France and Poland), the rate of deformation is small (10-20 ns / yr) to negligible (1-2 ns / yr ). In contrast, in areas of high seismicity, such as central Greece and central Italy, tectonic deformation is much greater and was measured between 50 and 150 ns / yr.

These results, according to Mr. Ganza, are comparable to similar results for Greece and Italy by other scientific groups. The study of tectonic deformation will be continued in cooperation with the Swedish Lantmierer (LM), with the aim of producing such maps on a yearly basis, including an increasing number of European GNSS stations.

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