Active Faults Determined by the Geological and Geophysical Methods Around Bursa: New Findings About the Strike-Slip Faults Cross-Cutting Pull-Apart Basins

Seyitoğlu G., Esat K., Tün M., Oruç B., Pekşen E., Mutlu S., ...Daha Fazla

73.Geological Congress of Turkey, Ankara, Türkiye, 24 - 28 Mayıs 2021, ss.854-855

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: Ankara
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.854-855
  • Kocaeli Üniversitesi Adresli: Evet

Özet

There are discussions on the number of branches of the North Anatolian Fault Zone in South Marmara, their routes and whether the active faults around Bursa can be evaluated within the scope of the North Anatolian Fault Zone or Eskişehir Fault Zone. Turkey’s fourth largest city, Bursa is growing rapidly, has experienced latest devastating earthquakes in 1850 and 1855. Although we have some predictions about the faults causing these earthquakes, the available information is limited. The active faults around Bursa constitute Bursa-west, Bursa-east and Yenişehir pull-apart basins. The structural data of these are collected and the fault locations and its characters are clarified. Unlike the new active fault map of Turkey; (1) the normal fault segments have been observed in the south of Bursa-west basin between Yaylacık and Çalı; (2) In the south of the Uludağ Core Complex, Soğukpınar Fault is a normal fault with negligible left lateral component and cannot be evaluated within the Eskişehir Fault Zone; (3) İnegöl Fault Zone and Oylat Fault segments are right-lateral strike-slip faults and they constitutes northwestern tip of Eskişehir Fault Zone extending to the north of Uludağ Core Complex. The possibility of NE-SW strike-slip faults, which cut the Bursa-west, Bursa-east and Yenişehir pull-apart basins and were not noticed due to the Quaternary basin fill, was stated in the previous studies / reports and their existence was tried to be confirmed by geophysical data. Seismic reflection studies were carried out along the lines determined by considering morphological data. All findings are evaluated together with the electrical resistivity and gravity data obtained from the study area. The first seismic reflection data indicate existence of the faults that cut the above-mentioned pull-apart basins and they operate as the southern branch of the North Anatolian Fault Zone. Block modelling studies are continuing to determine the seismicity of the fault branch and the amount of slip on it. This study has been carried out in the project UDAP-G-18-05 supported by AFAD.