Abstract
AbstractGeodetically derived velocities from Central Asia show that Northern Afghanistan, the Tajik Pamir, and northwestern Pakistan all move northward with comparable large velocities toward Eurasia. Steep velocity gradients, hence high strain rates, occur only across the Main Pamir Fault zone and with lesser magnitude between the northernmost Hindu Kush and the south and southeast margins of the Tajik Depression. Localized shortening is not apparent on any active India‐Hindu Kush crustal boundary; hence, crustal convergence between India and Eurasia in Central Asia is absorbed primarily on the northern and western margins of the Pamir. This concentrated strain on the Pamir margins is consistent with one, geometrically complex, interface between subducting Asian lithosphere and the Pamir. That interface might curve westward such that the Hindu Kush seismic zone is a continuation of the Pamir seismic zone, or alternatively, Hindu Kush earthquakes might occur in convectively unstable mantle lithosphere mechanically detached from surface faults.
Highlights
The Pamir-Hindu Kush region of Central Asia (Figure 1) serves as the best present-day example of ongoing subduction of continental lithosphere
Plain Language Summary Using Global Positioning System (GPS) measurements of surface velocities, we find that much of the relative motion between India and Eurasia in Central Asia is accommodated on a single crustal boundary on the north side of the Pamir, wrapping around the eastern and southern margins of the Tajik Depression
The GPS velocities (Figures 2 and 3 and Table S1) show ongoing convergence between India and Eurasia, with the steepest velocity gradients localized near the northern margin of the Pamir, consistent with other
Summary
The Pamir-Hindu Kush region of Central Asia (Figure 1) serves as the best present-day example of ongoing subduction of continental lithosphere. It is interpreted as a case of initiation of subduction in continental materials (Burtman & Molnar, 1993; Hamburger et al, 1992; Jay et al, 2017; Kufner et al, 2016; Negredo et al, 2007; Pegler & Das, 1998; Schneider et al, 2013; Sippl, Schurr, Yuan, et al, 2013), in contrast to the more common scenario where continental lithosphere follows oceanic lithosphere into a subduction zone. The distribution of earthquake hypocenters below the crust is conventionally divided into two parts, a northeastern part beneath the Pamir and a southwestern part beneath the Hindu Kush (Figure 1), distinguished by the Pamir zone dipping shallowly to the south and the Hindu Kush zone dipping nearly vertically to the north (Billington et al, 1977; Chatelain et al, 1980; Roecker, 1982; Roecker et al, 1980; Sippl, Schurr, Yuan, et al, 2013), with the two separated by a gap in hypocenters at depth. Fan et al (1994), Kufner et al
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
