Earthquakes are often related to the deformation of Earth’s crust. This deformation is mostly concentrated at the plates boundaries, where most of the earthquakes take place and where the horizontal component of tectonic deformation is stronger. This suggests that the spatial distribution of earthquakes and their frequency are related to the horizontal deformation rates. However, there is large record of intracontinental earthquakes taking place in regions that do not present significant horizontal deformation, but where vertical deformation is important. This may indicate that vertical deformation, which is usually associated to the downwelling or upwelling of the mantle, can also affect the seismicity. In order to better understand how the crustal deformation processes are related to the earthquake distribution, the authors combine present-day displacement measurements made in several regions of Europe (Résif-Renag data was used for France) to develop a 3D deformation model of the ground surface at continental scale, and they compare that model to the distribution of earthquakes.

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https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JB023451

Reference : Piña‐Valdés, J., Socquet, A., Beauval, C., Doin, M. P., D’Agostino, N., & Shen, Z. K. 3D GNSS Velocity Field sheds light on the Deformation Mechanisms in Europe: Effects of the vertical crustal motion on the distribution of seismicity. Journal of Geophysical Research: Solid Earth, e2021JB023451. https://doi.org/10.1029/2021JB023451 

Cartes de déformation et sismicité de l’Europe

Deformation and seismicity of Europe: (from left to right) Topography and major tectonic structures, horizontal velocities measured at 4238 GNSS station, vertical velocities, horizontal strain rate (2nd invariant), amplitudes and principal directions of the strain rate tensor (the color code represents the style of deformation: extension in blue and compression in red), smoothed seismicity rate map (aftershock contributions removed) © Piña-Valdés et al.