A statistical assessment of current seismic quiescence on the North Anatolian Fault Zone: Earthquake precursors

Abstract

The variations of the current seismicity rate on the North Anatolian Fault Zone in the beginning of 2009 have been analyzed based on the phenomenon of precursory seismic sequence before crustal main shocks. For this purpose, a statistical assessment is made to detect the seismic quiescence situation by using the standard normal deviate Z-value. Eight seismic quiescence regions are observed and quiescence anomalies in these regions have been observed since the beginning of 2005. On the Marmara part of the North Anatolian Fault Zone, four quiescence areas have been found on Silivri, in the Black Sea, around Izmit region and Çanakkale, Saros Gulf. On the Anatolian part of the North Anatolian Fault Zone, two quiescence areas have been observed on the Düzce fault and around the city of Amasya. Other anomalies have been observed around Erzincan, Elazığ and Bingöl regions on the eastern part of the North Anatolian Fault Zone. Due to the occurrences of the last strong earthquakes “M = 6.0 - Elazığ earthquake, 2010 March 08; M = 5.2 - Çanakkale W W (Saros Gulf) earthquake, 2010 November 03; M = 5.5 - Erzincan earthquake, 2011 September 22 and M = 5.1 - Marmara Ereğ- W W lisi (Tekirdağ) earthquake, 2012 June 07”, other seismic quiescence regions may contribute to the forecasting of impending main shocks. Spatial and temporal estimates of the future seismic hazard of the North Anatolian Fault Zone are provided based on the results.