Recent seismic and aseismic activity in the Ashikule stepover zone, NW Tibet

Three large earthquakes occurred in the Ashikule stepover zone, NW Tibet in 2008 (M w 7.1), 2012 (M w 6.2) and 2014 (M w 6.9). In this paper we use InSAR data to examine the 2008 event in detail, and place it in the context of both recent/possible future events and regional tectonic environment. We...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Geophysical journal international 2014-09, Vol.198 (3), p.1632-1643
Hauptverfasser: Bie, Lidong, Ryder, Isabelle
Format: Artikel
Sprache:eng
Online-Zugang:Volltext bestellen
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Three large earthquakes occurred in the Ashikule stepover zone, NW Tibet in 2008 (M w 7.1), 2012 (M w 6.2) and 2014 (M w 6.9). In this paper we use InSAR data to examine the 2008 event in detail, and place it in the context of both recent/possible future events and regional tectonic environment. We present InSAR data covering the coseismic and post-seismic phases of the 2008 event, and invert for slip distributions during both phases in order to examine the spatial relationship between earthquake rupture and afterslip. To account for the curved rupture trace as mapped in the field, we model the slip on a non-planar fault. A change in slip sense from left-lateral in the north to extensional in the south is consistent with the focal mechanism of aftershocks. We find that afterslip occurs around the perimeter of the coseismic slip, although in a patchy way, as seen in other normal faulting case studies. We calculate the Coulomb stress changes imparted by the 2008 earthquake on neighbouring faults, including stress loading on the subsequent rupture zones of the 2012 and 2014 earthquakes. We also compute the combined loading effect of the 2008, 2012 and 2014 earthquakes on the nearby Altyn Tagh Fault, which hasn't experienced a major earthquake since early last century. This study demonstrates that stepover zone failure can increase stresses on bounding strike-slip faults, which likely has relevance in analogous tectonic environments elsewhere in the world.
ISSN:0956-540X
1365-246X
DOI:10.1093/gji/ggu230