Convergence of 29 ± 1 mm/yr between the NW corner of the Indian plate and Asia is accommodated by a combination of thrust and strike‐slip faulting on prominent faults and apparent distributed deformation within the Hindu Kush, Pamir, South Tien Shan and Kohistan Ranges. An upper bound to the slip rate of known faults is obtained by ignoring distributed strain and rotation: convergence occurs on thrust faults north of the Peshawar Basin (13 ± 1 mm/yr) and in the Alai‐South Tien Shan (12 ± 2 mm/yr), and shear on the northeast‐trending northern Chaman‐Gardiz‐Konar system (18 ± 1mm/yr) and the Darvaz‐Karakul fault zone (11 ± 2 mm/yr). Slip rates on the Herat and Talas‐Ferghana faults are small (<2 mm/yr). Shortening not attributable to known active faults occurs within the Hindu Kush and central Pamir (16 ± 2 mm/yr) with concomitant east‐west extension in the latter of 9 ± 2 mm/yr. This diversity of strain styles confirms the importance of mechanical heterogeneity to continental tectonics and shows that the Pamir, although less than half the size, behaves more like Tibet than like a linear belt of localized deformation.

[1] Despite an overall sinistral slip rate of ≈3 cm/yr, few major earthquakes have occurred in the past 200 years along the Chaman fault system, the western boundary of the India Plate with the Eurasia Plate. GPS and InSAR data reported here indicate sinistral shear velocities of 8-17 mm/yr across the westernmost branches of the fault system, suggesting that a significant fraction of the plate boundary slip is distributed in the fold and fault belt to the east. At its southernmost on-land segment (≈26 N), near the triple junction between the Arabia, Eurasia, and India Plates, we find the velocity across the Ornach Nal fault is 15.1 +13.4 +16.9 mm/yr, with a locking depth probably less than 3 km. At latitude 30 N near the town of Chaman, Pakistan, where a M6.5 earthquake occurred in 1892, the velocity is 8.5 +6.8 +10.3 mm/yr and the fault is locked at approximately 3.4 km depth. At latitude 33 N and further north, InSAR data indicate a velocity across the Chaman fault of 16.8 AE 2.7 mm/yr. The width of the plate boundary varies from several km in the south where we observe ≈2 mm/yr of convergence near the westernmost strike-slip faults, to a few hundreds of km in the north where we observe 6-9 mm/yr of convergence, and where the faulting becomes distinctly transpressional. The shallow locking depth along much of the transform system suggests that earthquakes larger than those that have occurred in the historical record would be unexpected, and that the recurrence interval of those earthquakes that have occurred is of the order of one or two centuries, similar in length to the known historical record.

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Surface deformation associated with the 27 August 1931 earthquake near Mach in Baluchistan is quantified from spirit‐leveling data and from detailed structural sections of the region interpreted from seismic reflection data constrained by numerous well logs. Mean slip on the west dipping Dezghat/Bannh fault system amounted to 1.2 m on a 42 km × 72 km thrust plane with slip locally attaining 3.2 m up dip of an inferred locking line at ∼9 km depth. Slip also occurred at depths below the interseismic locking line. In contrast, negligible slip occurred in the 4 km near the interseismic locking line. The absence of slip here in the 4 years following the earthquake suggests that elastic energy there must either dissipate slowly in the interseismic cycle, or that a slip deficit remains, pending its release in a large future earthquake. Elastic models of the earthquake cycle in this fold and thrust belt suggest that slip on the frontal thrust fault is reduced by a factor of 2 to 8 compared to that anticipated from convergence of the hinterland, a partitioning process that is presumably responsible for thickening of the fold and thrust belt at the expense of slip on the frontal thrust. Near the latitude of Quetta, GPS measurements indicate that convergence is ∼5 mm/yr. Hence the minimum renewal time between earthquakes with 1.2‐m mean displacement should be as little as 240 years. However, when the partitioning of fold belt convergence to frontal thrust slip is taken into account the minimum renewal time may exceed 2000 years.

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