The 2008 Nura Mw6.7 earthquake: A shallow rupture on the Main Pamir Thrust revealed by GPS and InSAR

Abstract

Main Pamir Thrust Global positioning system (GPS) Interferometric synthetic aperture radar (InSAR) Coseismic deformation Interseismic deformation Southern Tianshan a b s t r a c t The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar (InSAR) measurements of its coseismic ground deformation that are available for a major earthquake in the region. Analysis of the InSAR data shows that the earthquake ruptured a secondary fault of the Main Pamir Thrust for about 20 km. The fault plane striking N46 E and dipping 48 SE is dominated by thrust slip up to 3 m, most of which is confined to the uppermost 2e5 km of the crust, similar to the nearby 1974 Mw7.0 Markansu earthquake. The elastic model of interseismic deformation constrained by GPS measurements suggests that the two earthquakes may have resulted from the failures of two high-angle reverse faults that are about 10 km apart and rooted in a locked d ecollement at depths of 5e6 km. The elastic strain is built up by a freely creeping d ecollement at about 16 mm/a.

Source model of the 2015 Mw 6.4 Pishan earthquake constrained by interferometric synthetic aperture radar and GPS: Insight into blind rupture in the western Kunlun Shan

“…An alternative explanation is that the shallow asperity identified by our modeling indeed expresses a brittle failure that occurred either during the main shock or more likely during an afterslip that could occur in shallow parts of a coseismically activated fault [ Scholz , ]. Recently, several thrusting earthquakes observed elsewhere in Asia have ruptured the uppermost 10 km crust [e.g., Nissen et al ., ; Elliott et al ., ; Qiao et al ., ]. In particular, the 2008 M w 6.6 Nura, Kirgizstan earthquake, which occurred at the foothill of the Trans‐Alai Range of northern Pamir, had a very shallow focal depth of 3–4 km [ Sippl et al ., ].…”

“…Under this circumstance, the barrier could represent a potential earthquake comparable to but more destructive than the 2015 event, unless it deform aseismically [e.g., Fielding et al ., ; Nissen et al ., ]. It is not rare that a deep thrusting event is followed by a shallower earthquake at approximately the same location, sometimes sooner than expected, for example, the 2003–2004 Qaidam earthquake sequence in northern Tibet [ Elliott et al ., ] and the 1974–2008 Markansu‐Nura earthquake sequence in northern Pamir [ Qiao et al ., ]. Even being small in magnitude, the shallower one may induce relatively stronger surface effects, causing more damages to vulnerable areas.…”

Investigation of Relation between Solar Activity and Earthquakes with Deep Learning Method

“…With the development of sensing technologies, including GPS and InSAR [11], a massive amount of data on SA has been accumulated. Furthermore, the solarearth coupling can be characterized as a non-linear dynamical system.…”

Analysis of Long-Term Gravitational and Seismic Measurements in the Pamir - Tien-Shan Region

“…It is assumed that regional earthquakes focus generation is direct consequence of submeridional compression high tensions, the energy source of which is pressure exerted by the Hindostan plate from the South [1]. Over several last centuries, more than ten earthquakes of M7.0 have occurred in the Pamir and Tien-Shan regions [2]. However, the complex and rugged terrain of the study area make it impossible to conduct ground-based studies of geodynamic and deformation processes based on traditional geophysical and geodetic measurements.…”