Tectonic and geomorphic setting of the Pamir Plateau: Insights from InSAR and teleseismic analysis of the 2015 Lake Saurez and 2016 Muji fault earthquake sequence
Abstract
The Pamir Plateau lies on the western edge of the India- Eurasia collision zone and has been the sight of complex subduction regime in the past 50 Ma. In our study, we focus on two earthquakes and their aftershocks that occurred between December 2015 and December 2016. The first earthquake (Mw7.2), on 7 December 2015 between the Karakoram and Darwas fault systems, was sinstral strike slip in nature. The earthquake on 25 November (Mw6.6) occurred on the western end of Muji Fault, a dextral strike slip fault with an avg slip rate of 4mm/yr. We aim to better understand the structure, stress and deformation patterns in the northern and central Pamir plateau by analyzing InSAR, teleseismic, and optical data for these events and their aftershocks. We aim to better understand the structure, stress and deformation patterns in the northern and central Pamir plateau by analysing InSAR, teleseismic, and optical data for these events and their aftershocks. We constrain the fault geometry by precisely relocating aftershocks using the double difference technique implemented in HypoDD (Waldhauser & Ellsworth 2000). We used the Green's functions of Okada (1992) to invert for slip on the fault with rectangular dislocation and edgreen to numerically invert for the slip in a layered medium (Wang et al. 2003). The surface rupture of the December 2015 Lake Saurez earthquake shows evidence of multiple segments and step-overs. The combination of data sets used in this study highlights the existence of a seismic gap south of Lake Karakul as well as coupling between the Muji and Darwas-Karakoram fault systems. Mapping of past ruptures shows that the Sarez fault continues along the eastern coast of Lake Karakul almost until the Muji fault. With near field geodetic data in the form of InSAR, we can get a better insight into complex fault structures as well as post seismic slip and strain along the faults and its surroundings. We emphasize the role of smaller faults and their interactions in accommodating the overall strain in the Pamir region and their effect on estimating local seismic hazard.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.T51J..08N
- Keywords:
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- 1207 Transient deformation;
- GEODESY AND GRAVITY;
- 1209 Tectonic deformation;
- GEODESY AND GRAVITY;
- 7223 Earthquake interaction;
- forecasting;
- and prediction;
- SEISMOLOGY;
- 8158 Plate motions: present and recent;
- TECTONOPHYSICS