New insights into the structural model of the Makran subduction zone by fusion of 3D inverted geophysical models

• Published in: Journal of Asian earth sciences 2020-02, Vol.188, p.104075, Article 104075
• Main Authors: Nasri, Sara, Nejati Kalate, Ali, Roshandel Kahoo, Amin, Soleimani Monfared, Mehrdad
• Format: Article
• Language: English
• Subjects: Gravity modelling; Image fusion; Magnetic inversion; Makran subduction zone; Structural complexity
• ISSN: 1367-9120; 1878-5786
• DOI: 10.1016/j.jseaes.2019.104075

•We have improved the 3D model of the Makran subduction zone and its structures.•An integrated modeling strategy was presented for geophysical data from complex media.•A unique model was derived by image fusion, containing shallow and deep information.•We introduced an efficient strategy for extracting related information from geophysical data. Geological modeling by geophysical data in the Makran subduction zone is a challenging task which comes from its extreme structural and geological complexity. Different geological models were presented for this zone in previous studies by the use of various sources of information. Among these studies, numerous geophysical models were introduced to illustrate depth, geometry and location of the subduction zone and definition boundaries with adjacent zones. However, structural complexity of the media and high degree of variation in geological units reduce accuracy of geophysical model derivation. In this study, an integrated strategy via model fusion for geological model building of the Makran subduction zone was presented using gravity and magnetic data. In the presented strategy, gravity and magnetic models were integrated through fusing procedure. Herewith airborne magnetic and gravity data were inverted by fine gridding and solving large scale problems for each set of potential field data. While magnetic model inherently was able to reveal near surface structures, gravity data modeled large depth anomalies. Afterwards, a discrete wavelet transform rule was used for fusion magnetic and gravity models to derive a unique model containing advantage of both sets of data. The fused model revealed more detail of the Makran zone structure, location of the subduction zone and steep dip faults. The final models proposed depth of 40 km for the top of the oceanic crust with variation in thickness from 5 to 8 km, basin ward. The subduction zone located 200 km in the onshore and it shows a very low dip.