Detection of fault segments based on P–T dihedra analysis along the North Tabriz fault, NW Iran

Abstract

Detection of fault segments is an essential step for tracking main transverse faults. General observations from field studies as well as attitude measurements can give an overall understanding of the lengths of the segments, but these are not always sufficient to accurately identify and characterize them. In this study, we analyze P–T dihedra variations based on their eigenvalues to detect fault segments. The anomalies of local paleostress distribution aid us to detect the segment boundaries. This study focuses on the Northwestern, Central, and Southeastern sectors of the North Tabriz Fault (NTF). Fault azimuth distribution and eigenvalue anomalies as well as the fault attitudes for each interval distance have been used to distinct segment boundaries. The results are verified by checking the presence of the transverse faults at the proposed sites during fieldwork. Results show a new structural arrangement integrated by the already documented NTF segments, combined with 6 related transverse faults. In this way, we confirm the earlier reported segments, and we improve the NFT characterization by introducing new segments bounded by transverse faults.