Mechanics of the Kalabagh Fault, northwest Himalayan fold and thrust belt (convergence zone of India and Eurasia), using SAR interferometry and CFS

Frontiers in Earth Science

Earth Science

Farhan Javed¹  Muhsan Ehsan²  Mohammed S. Fnais³  Kamal Abdelrahman³  Rizwan Ahmed⁴  Waqar Ali Zafar⁵  Mansoor Aziz Qureshi⁶ 

[1] Centre for Earthquake Studies, National Center for Physics, Islamabad, Pakistan;Department of Earth and Environmental Sciences, Bahria School of Engineering and Applied Sciences, Bahria University, Islamabad, Pakistan;Department of Geology and Geophysics, College of Science, King Saud University, Riyadh, Saudi Arabia;Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan;Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan;Centre for Earthquake Studies, National Center for Physics, Islamabad, Pakistan;Geology Department, Lund University, Lund, Sweden;

关键词: SAR interferometry;    creeping;    inversion;    Coulomb stress;    strike–slip fault;   

DOI  :  10.3389/feart.2023.1231408

 received in 2023-05-30, accepted in 2023-07-17,  发布年份 2023

来源: Frontiers

【 摘 要 】

The Kalabagh strike–slip fault, which is characterized by right-lateral movement, is part of the northwestern Himalayan foreland fold and thrust belt in Pakistan. This structure marks the western and eastern terminations of the Salt Range and Surghar Ranges, respectively. No significant (>M6) earthquakes have been reported along the Kalabagh Fault in recent decades. Here, we take advantage of space-borne Sentinel-1A SAR interferometry to gain insight into the mechanics of faulting, aseismic creeping, and stress loading of the seismic cycle on the Kalabagh Fault spanning over approximately 7 years. In this study, we also removed the tropospheric effects using the Generic Atmospheric Correction Online Service data from the rate map. We further resolved the LOS deformation into both horizontal and vertical deformations. Our Bayesian inversion indicates that the fault experiences significant horizontal and vertical displacements. The fault’s southern and northern segments exhibit a creeping rate of approximately ∼4.2 ± 1.3 to 4.8 ± 1.6 mm/year, respectively, while the central section does not display any horizontal creeping. We found that the creeping is confined between 0 and ∼2.7 ± 1.1 km depth at the northern section and 0 and ∼3.9 ± 1.1 km on the southern section of the faults. Nevertheless, we found that the vertical creeping of ∼10 mm/year is confined between 0.5 and 6 km depth in the central segment of the fault. Moreover, our model does not resolve the interseismic slip at depth on the Kalabagh Fault. Our results affirm that Kalabagh Fault is creeping, and the internal deformation due to the presence of a thick salt layer over the decollement facilitates the creeping on this fault. In addition, Coulomb stress modeling depicts that the creeping on the Kalabagh Fault increases the Coulomb stress changes in the northern section of the KBF.

【 授权许可】

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Copyright © 2023 Zafar, Javed, Ahmed, Ehsan, Abdelrahman, Fnais and Qureshi.