Fault geometry of 2015, Mw7.2 Murghab, Tajikistan earthquake controls rupture propagation: Insights from InSAR and seismological data

Abstract

Combining space-based geodetic and array seismology observations can provide detailed information about earthquake ruptures in remote regions. Here we use Landsat-8 imagery and ALOS-2 and Sentinel-1 radar interferometry data combined with data from the European seismology network to describe the source of the December 7, 2015, Mw7.2 Murghab (Tajikistan) earthquake. The earthquake reactivated a ∼79 km-long section of the Sarez-Karakul Fault, a NE oriented sinistral, trans-tensional fault in northern Pamir. Pixel offset data delineate the geometry of the surface break and line of sight ground shifts from two descending and three ascending interferograms constrain the fault dip and slip solution. Two right-stepping, NE-striking segments connected by a more easterly oriented segment, subvertical or steeply dipping to the west were involved. The solution shows two main patches of slip with up to 3.5 m of left lateral slip on the southern and central fault segments. The northern segment has a left-lateral and normal oblique slip of up to a meter. Back-projection of high-frequency seismic waves

The 2015 Mw7.2 Sarez Strike‐Slip Earthquake in the Pamir Interior: Response to the Underthrusting of India's Western Promontory

“…It is bounded by a northeastern segment with a length of km and a strike of , and a southwestern segment with a length of km and strike of (Table S3). Our solution agrees well with the fault model of Sangha et al () (Figure S6), except that all our model segments dip more steeply. In addition to the Sentinel‐1 interferograms presented here, Sangha et al () included three interferometric pairs from the ALOS‐2 mission.…”

“…Our solution agrees well with the fault model of Sangha et al () (Figure S6), except that all our model segments dip more steeply. In addition to the Sentinel‐1 interferograms presented here, Sangha et al () included three interferometric pairs from the ALOS‐2 mission. The longer wavelength (L band) of ALOS‐2 provides valuable near‐field information, similar to the pixel offset data used in this study.…”

“…The model of Sangha et al () and our uniform and our data‐driven patch slip model all show a similar slip pattern (Figure S8), but the derived slip parameter uncertainties highlight the strength of the data‐driven patch resolution. The slip parameter uncertainties are generally lower and depth independent.…”

“…The longer wavelength (L band) of ALOS‐2 provides valuable near‐field information, similar to the pixel offset data used in this study. From SW to NE, our segments dip northwest, northwest, and southeast; those of Sangha et al () southeast, northwest, and northwest.…”

“…The Pamir interior is seismically less active, both in long‐term global earthquake catalogs (Storchak et al, ) and observed by a dense local seismic network (Schurr et al, ). On 7 December 2015, a M w 7.2 strike‐slip earthquake occurred in the interior of the Pamir along the Sarez‐Karakul fault system (SKFS) with the epicenter near Lake Sarez (Figure a) (Sangha et al, ; USGS, ). The earthquake killed two persons and left more than a thousand homeless.…”