Acta Geophysica

, Volume 66, Issue 6, pp 1273–1290 | Cite as

Stress studies in the Central Alborz by inversion of earthquake focal mechanism data

  • Shahrokh Pourbeyranvand
Research Article - Solid Earth Sciences


The Alborz is one of the most important seismotectonic provinces in Iran. Furthermore, emplacement of Tehran as a mega city in southern part of the Alborz intensifies the seismic vulnerability in this area. In this study, the focal mechanism data from teleseismic and local seismic networks are used for stress tensor inversion. The earthquake focal mechanisms in the Central Alborz are divided into several groups with respect to their location. Two different stress tensor inversions, linear and nonlinear, are used for obtaining the principal stress orientations. The results show spatial variations in tectonic stress field, consistent with fault orientations and faulting mechanisms. The maximum compressional stress directions obtained in this study are confirmed by fast S-wave polarization axes reported by a previous shear wave splitting study. The maximum horizontal stress directions are also compared with GPS strain rates. The results indicate a partitioning of deformation in the area due to regional stresses along preexisting faults.


Deformation partitioning Earthquake Focal mechanism Inversion Stress Shear wave splitting 



The author acknowledges International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran, for supporting this project (activity code: 9804) and deeply appreciate B. Lund from Uppsala University, M. Tatar from IIEES, H. Shomali from University of Tehran, and Th. Arnadotir from Iceland University for providing the necessary codes, helpful comments, and their kind collaborations. And last but not least, I thank the anonymous reviewers of the journal, who I owe the improvements in all aspects and every single word of this paper, to their many careful and precise corrections.


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Copyright information

© Institute of Geophysics, Polish Academy of Sciences & Polish Academy of Sciences 2018

Authors and Affiliations

  1. 1.Seismology DepartmentInternational Institute of Earthquake Engineering and SeismologyTehranIran

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