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

Acta Geophysica

Shahrokh Pourbeyranvand¹ 

[1] International Institute of Earthquake Engineering and Seismology

关键词: Deformation partitioning;    Earthquake;    Focal mechanism;    Inversion;    Stress;    Shear wave splitting;   

DOI  :  10.1007/s11600-018-0207-1

学科分类：地球科学(综合)

来源: Polska Akademia Nauk * Instytut Geofizyki

【 摘 要 】

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.

【 授权许可】

Unknown