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Journal of Seismology

, Volume 22, Issue 6, pp 1563–1578 | Cite as

Revised seismotectonic model of NE Italy and W Slovenia based on focal mechanism inversion

  • Gianni Bressan
  • Carla Barnaba
  • Pierluigi Bragato
  • Maurizio Ponton
  • Andrea Restivo
ORIGINAL ARTICLE

Abstract

The study is focusing on the stress and strain inversions from focal mechanisms in a revised seismotectonic zonation of northeastern Italy and western Slovenia. The recent increase of monitoring capability of the local seismic network, the updated geological-structural model of the area, and the novelties emerged from studies on the spatial organization of the seismicity allowed a redefinition of the seismotectonic zones. The stress and strain tensors inversion is inferred from 203 focal mechanisms, corresponding to earthquakes occurred between 1984 and 2016 with coda-duration magnitude range from 2.0 to 5.6. The inverted stress domains reveal an articulated picture of the interaction of the Adria microplate with the Eurasian plate. A dominant strike-slip stress field characterizes the eastern part of the area, while the seismotectonic zones of the central part are undergoing to thrusting regime. The stress pattern inferred in the western part of the study area outlines a complex picture with prevailing strike-slip regime and dominant compression only in a seismotectonic zone. The comparison of stress and strain tensor orientations evidences a relative uniformity of the crustal strength in the eastern and northwestern zones of the study area. The central and western zones appear to be characterized by planes of mechanical weakness not favorably oriented for failure with respect to the stress tensor.

Keywords

Seismotectonics Focal mechanisms Stress and strain tensor inversion 

Notes

Acknowledgements

We thank the two anonymous reviewers for constructive comments that greatly improved the paper. We benefited of the valuable contribution of A. Peresan. We thank also A. Magrin, I. Dreossi, S. Urban, and G. Rossi for their help and useful discussions.

Funding information

The local seismic network is managed by the Sezione Centro di Ricerche Sismologiche of the Istituto Nazionale di Oceanografia e Geofisica Sperimentale—OGS with the financial contribution of the Regione Friuli Venezia Giulia.

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Copyright information

© Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.OGS—Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Centro Ricerche SismologicheUdineItaly
  2. 2.Dip. Di Matematica e GeoscienzeUniversità degli studi di TriesteTriesteItaly

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