On February 6, 2023, two large earthquakes occurred near the Turkish town of Kahramanmaraş. The moment magnitude (Mw) 7.8 mainshock ruptured a 310 km-long segment of the left-lateral East Anatolian Fault, propagating through multiple releasing step-overs. The Mw 7.6 aftershock involved nearby left-lateral strike-slip faults of the East Anatolian Fault Zone, causing a 150 km-long rupture. We use remote-sensing observations to constrain the spatial distribution of coseismic slip for these two events and the February 20 Mw 6.4 aftershock near Antakya. Pixel tracking of optical and synthetic aperture radar data of the Sentinel-2 and Sentinel-1 satellites, respectively, provide near-field surface displacements. High-rate Global Navigation Satellite System data constrain each event separately. Coseismic slip extends from the surface to about 15 km depth with a shallow slip deficit. Most aftershocks cluster at major fault bends, surround the regions of high coseismic slip, or extend outward of the ruptured faults. For the mainshock, rupture propagation stopped southward at the diffuse termination of the East Anatolian fault and tapered off northward into the Pütürge segment, some 20 km south of the 2020 Mw 6.8 Elaziğ earthquake, highlighting a potential seismic gap. These events underscore the high seismic potential of immature fault systems.

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.

Sepehr & Cosgrove, 2004). Complex fault geometry causes shortening in the hanging wall that is accommodated by flexural slip, a type of plastic deformation that results from slip on multiple bedding planes in sedimentary strata (

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