The September 26, 2019 Silivri Earthquake (Mw=5.6), NW Türkiye

Abstract

The September 26, 2019 Silivri earthquake (MW=5.6-5.8) occurred along the North Anatolian Fault Zone segments extending beneath the Marmara Sea. In the present study the teleseismic P waveforms and 20-year long background seismicity of the earthquake (MW=5.6-5.8) have been analyzed. Point-source inversion of the teleseismic P waveforms revealed that the earthquake was due to oblique faulting and released a seismic moment of 3.2 x 1017 Nm (MW=5.6). The frequency-magnitude distributions (FMDs) for the background seismicity have been calculated for 5-year long time windows after the 1999 İzmit earthquake. The considerable decrease of b-value of the FMDs just before the 2019 Silivri earthquake has been interpreted as stress increase along the fault segments which provides a reasonable clue for the occurrence of the earthquake. The FMD distribution for the 5 year-long time windows before the 2019 Silivri earthquake suggests a recurrence time interval of 168 years and occurrence probability of %16 within the next 30 years for a Mw=7.5 earthquake.