Ongoing Postseismic Deformation of the Mw 7.1, October 23, 2011 Van (Turkey) Earthquake from GPS and InSAR Time Series


Akoğlu A. M. , Çeliker D., Özdemir A. , Çakır Z., Jonsson S., Doğan U. , et al.

American Geophysical Union, California, Amerika Birleşik Devletleri, 9 - 13 Aralık 2019, ss.1

  • Basıldığı Şehir: California
  • Basıldığı Ülke: Amerika Birleşik Devletleri
  • Sayfa Sayısı: ss.1

Özet


The interaction of the strike slip and thrust faults in the Turkish-Iranian Plateau that accommodates the convergence between the Eurasian and Arabian plates in the region is still a matter of debate. The October 23rd, 2011, Mw 7.1, Van (Turkey) earthquake that took place 8 years ago is therefore considered as a key event that provides an opportunity to refine our understanding of the active continental deformation in the plateau. Added to that the shallow slip deficit on the main causative fault discovered by coseismic studies signifies the importance of monitoring the post-earthquake deformation in the region due to its proximity to the Van city center.

Here we will be presenting an up-to-date analysis of the postseismic deformation by complementing the data from eight near-field GPS campaigns with up to 5 years of InSAR measurements from the Sentinel-1 satellites between 2014 and 2019. Persistent scatterer InSAR method is used to calculate the surface deformation maps from both the descending and ascending orbits to reveal the extent and the nature of the postseismic movement. The geodetic data clearly indicate that the postseismic ground motion following the earthquake has not ceased yet, making it one of the longest lasting postseismic deformation following a thrust faulting event in the world.

One of the key features observed in the velocity maps is the presence of shallow afterslip along a NE-SW extending sharp discontinuity that is different than the up-dip trace of the causative coseismic fault that lies between Lake Van to the west and Lake Erçek to the east. While the westernmost part of the discontinuity coincides with the earlier recognized aseismic slip on the Bostaniçi (Beyüzümü) Fault to the south that crosses the Van city center, the remaining part of the discontinuity veers towards northeast and reaches the Kozluca Fault on the western coast of Lake Erçek, confirming our earlier coseismic study where that fault was proposed as being part of the main coseismic rupture bounding it to the east.