EGU2020-13052
https://doi.org/10.5194/egusphere-egu2020-13052
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

How Has GPS Velocity Field Changed Along the 1999 Izmit Rupture 20 Years After the 1999 Izmit, Turkey Earthquake?

Seda Özarpacı1, Uğur Doğan1, Semih Ergintav2, Ziyadin Çakır3, Alpay Özdemir1, Michael Floyd4, and Robert Reilinger4
Seda Özarpacı et al.
  • 1Yildiz Technical University, Istanbul, Turkey
  • 2Bogazici University, Kandilli Observatory and Eartquake Research Institute, Istanbul, Turkey
  • 3Istanbul Technical University, Department of Geological Engineering, Istanbul, Turkey
  • 4Massachusetts Institute of Technology, Department of Earth, Atmospheric and Planetary Sciences, Boston, USA

A seismic gap along the western segment of the North Anatolian Fault, in the Marmara-Izmit region, was identified before the 1999 M7.6, Izmit and M7.4 Duzce earthquakes, so the region along the coseismic fault has been monitored with geodetic techniques for decades, providing well defined pre-, co- and post-seismic deformations. Here, we report new continuous and survey GPS measurements with near-fault (~2 – 10 km to the fault) and far-fault (~50 – 70 km from the fault) stations, including 7 years (2013 – 2019) of continuous observations, and 5 near-fault campaigns (every six months between 2014 – 2016) to further investigate postseismic deformation. GPS observations were processed with the GAMIT/GLOBK (v10.7) GNSS software. We used these observations to estimate the spatial distribution of current aseismic after-slip, along the 1999 Izmit rupture. We also searched for spatiotemporal changes of shallow creep events along the surface trace. With elastic models and GPS observations, we determined a shallow creep rate that reaches a maximum around the epicenter of the 1999 Izmit earthquake of about 12.7 ± 1.2 mm/yr, consistent with published InSAR results. Creep rates decrease both east and west of the epicentral region. Moreover, we show that broad-scale postseismic effects that diminish logarithmically, continue at present. (This study is supported by TUBITAK 1001 project no: 113Y102 and 117Y278)

How to cite: Özarpacı, S., Doğan, U., Ergintav, S., Çakır, Z., Özdemir, A., Floyd, M., and Reilinger, R.: How Has GPS Velocity Field Changed Along the 1999 Izmit Rupture 20 Years After the 1999 Izmit, Turkey Earthquake?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13052, https://doi.org/10.5194/egusphere-egu2020-13052, 2020

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