3D GNSS Velocity Field Sheds Light on the Deformation Mechanisms in Europe: Effects of the Vertical Crustal Motion on the Distribution of Seismicity. Issue 6 (31st May 2022)

• Record Type: Journal Article
• Authors: Piña‐Valdés, Jesús; Socquet, Anne; Beauval, Céline; Doin, Marie‐Pierre; D'Agostino, Nicola; Shen, Zheng‐Kang
• Is Part Of: Journal of geophysical research. Volume 127:Issue 6(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-31
• Subjects: strain rate -- earthquake recurrence -- seismicity spatial distribution; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2021JB023451
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: Crustal deformation and seismicity in Europe are still poorly understood. Seismic activity is classically ascribed to crustal strain rates generated by edge‐driven tectonic forces. However, crustal deformation is not only due to tectonic loading, but can also be related to isostatic and mantellic processes that induce additional stress and strain on the crust by flexure. The influence that those processes have on seismic activity, as well their interaction, is still controversial. The main limitation to study it is because the deformation and its causal mechanisms are usually analyzed separately in small regions. We present here a 3D secular velocity field that covers Eurasia and its plate boundaries including 4, 863 Global Navigation Satellite System stations obtained by combining 10 different datasets. We have developed a method based on spatial filtering to identify outliers and smooth the velocity field, and have computed both strain and uplift rate maps that are interpreted in the light of the different driving processes that contribute to the 3D deformation in Europe. The vertical and horizontal deformation features are compared with seismic rates obtained from the spatial and temporal distribution of the seismicity in Europe. Our results suggest that is not possible to explain the seismicity in Europe with edge‐driven horizontal tectonic forces only. In some areas markers of the crustal flexure such as the vertical velocity field and its derivative, resulting from buoyancy‐driven processes, may help to interpret earthquake distribution. Plain Language Summary: 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 frequencies 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, we combine present‐day displacement measurements made in several regions of Europe to develop a 3D deformation model of the ground surface at continental scale, and we compare that model to the distribution and the occurrence rates of earthquakes. Key Points: We construct a 3D secular continental‐scale Global Navigation Satellite System velocity field over Europe A continental‐wide surface deformation field provides a means of estimating deformation associated with bulk elastic deformation versus crustal flexure The spatial distribution of the seismicity correlates regionally with Strain‐rate and vertical velocity patterns, associated to tectonic deformation and crustal flexure respectively