3-D crustal structure along the North Anatolian Fault Zone in north-central Anatolia revealed by local earthquake tomography


Yolsal-Cevikbilen S., Biryol C. B. , Beck S., Zandt G., Taymaz T. , Adiyaman H. E. , ...Daha Fazla

GEOPHYSICAL JOURNAL INTERNATIONAL, cilt.188, ss.819-849, 2012 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 188 Konu: 3
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1111/j.1365-246x.2011.05313.x
  • Dergi Adı: GEOPHYSICAL JOURNAL INTERNATIONAL
  • Sayfa Sayıları: ss.819-849

Özet

3-D P-wave velocity structure and Vp/Vs variations in the crust along the North Anatolian Fault Zone (NAFZ) in north-central Anatolia were investigated by the inversion of local P- and S-wave traveltimes, to gain a better understanding of the seismological characteristics of the region. The 3-D local earthquake tomography inversions included 5444 P- and 3200 S-wave readings obtained from 168 well-located earthquakes between 2006 January and 2008 May. Dense ray coverage yields good resolution, particularly in the central part of the study area. The 3-D Vp and Vp/Vs tomographic images reveal clear correlations with both the surface geology and significant tectonic units in the region. We observed the lower limit of the seismogenic zone for north-central Anatolia at 15 km depth. Final earthquake locations display a distributed pattern throughout the study area, with most of the earthquakes occurring on the major splays of the NAFZ, rather than its master strand. We identify three major high-velocity blocks in the mid-crust separated by the Izmir-Ankara-Erzincan Suture and interpret these blocks to be continental basement fragments that were accreted onto the margin following the closure of Neo-Tethyan Ocean. These basement blocks may have in part influenced the rupture propagations of the historical 1939, 1942 and 1943 earthquakes. In addition, large variations in the Vp/Vs ratio in the mid-crust were observed and have been correlated with the varying fluid contents of the existing lithologies and related tectonic structures.