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The Sulaiman Fold Thrust (SFT) in Central Pakistan formed during the India-Eurasia collision in the late Cenozoic. However, the mechanics of shortening of the brittle crust at time scales of seismic cycles is still poorly understood. Here, we use radar interferometry to analyze the deformation associated with the 2015 magnitude (Mw) 5.7 Dajal blind earthquake at the eastern boundary of the SFT. We use kinematic inversions to determine the distribution of slip on the frontal ramp and of flexural slip along active axial surfaces for the forward- and backward-verging two end-member models: a double fault-bend-fold system and a fault-propagation-fold. In both models, a décollement branches into a shallow ramp at approximately 7.5 km depth with coseismic folding in the hanging wall. The Dajal earthquake ruptured the base of the Boundary Thrust buried under the sediment from the Indus-River floodplain, representing fault-bend or fault-propagation folding some 30 km off its nearest surface exposure.

On 24 September 2019, an Mw 5.9 earthquake struck near the Mangla reservoir in northeastern Pakistan and resulted in 39 fatalities and 746 serious injuries, making it the deadliest earthquake in the region since the 2005 Mw 7.6 Kashmir earthquake. Here, we integrate geodetic, seismic, and field observations to characterize the source properties and impact of the Mirpur earthquake as well as investigate whether it might be a reservoir-induced event. From inverting Interferometric Synthetic Aperture Radar data, we find that a fault with strike ∼310°, dip ∼6°, and rake ∼117° is the optimal source, with slip concentrated between 5 and 6 km depth. This is consistent with our relocated aftershocks depth distribution and the lack of surface rupture observed in the field. Therefore, we infer that the earthquake ruptured the Main Himalayan Thrust (MHT). The event’s shallow depth might explain the extensive damage caused despite its moderate magnitude, with a maximum shaking intensity of VIII based on our field survey. The survey also revealed extensive damages associated with earthquake-induced liquefaction. Our modeling shows that loading due to increased reservoir water level in the three months before the Mirpur earthquake led to Coulomb stress increase of ∼7–10 kPa on the rupture plane. However, this effect is ∼10 times smaller than the Coulomb stress increase due to the 2006 Mangla earthquake, and the Mirpur earthquake only occurred ∼1–2 weeks after peak water level. These suggest that pore pressure diffusion contributed to promoting the fault rupture at a time when it is close to failure due to accumulated stress from inter-seismic loading. Because the Mirpur earthquake resulted in a stress increase of >0.2 MPa on the surrounding sections of the MHT and nearby faults, future rupture of these faults is a significant hazard and proper management of reservoir operations is necessary to prevent further elevating the seismic risk.