A STUDY ON ACTIVITY OF THE NORTHERN BRANCH OF THE NORTH ANATOLIAN FAULT THE 17TH AUGUST 1999 MARMARA EARTHQUAKE

5th International Scientific Conference - SGEM2005, www.sgem.org, SGEM2005 Conference Proceedings/ ISBN: 954-918181-2, June 13-17, 2005, 579- 586pp

ABSTRACT

This study aims at understanding the activity of northern branch of the North Anatolian
Fault. The Avcılar and adjacent areas were chosen as a study area as the Marmara
Earthquake had caused severe damage and fatalities in Avcilar. We carried out a fieldwork in
the area and found out surface fractures. We then integrated in to our map existing
seismological-seismic and damaged distribution data.
We propose that the damage to the W of İstanbul, especially in Avcilar was caused
mainly by re-activation of younger faults related to northern branch of the NAF, rather than
local soil conditions. Such an affect of these faults caused may be an indication of activity of
the northern branch of the NAF. The implies that the broken segment of the Marmara
Earthquake is longer than that previously assumed, extending into the Marmara Sea.