GPS-derived source parameters of the 2014 North Aegean earthquake (Mw 6.9)

Abstract

We analyzed GPS data to investigate the source parameters of the 2014 North Aegean earthquake (Mw 6.9). We simultaneously inverted strike, dip, rake, average slip, moment, size, and location of the mainshock rupture using coseismic displacements. Wealso investigated static stress change associated with the mainshock and its influence on aftershock activity. Previous solutions of focalmechanism showed that mainshock has a nearly pure strike-slip nature. Our results also indicate that the mainshock has a right lateralstrike-slip mechanism with a substantial extensional component. Average coseismic slips are 48 cm and 25 cm on the horizontal andvertical axis, respectively. Coseismic displacements reach up to 51.35 ± 4.55 mm at ~60 km from the hypocenter (LEMN station). Itappears that the mainshock ruptured a fault section approximately 28 km deep and 70 km long and generated a stress drop along theruptured segment ranging between 3 and 10 bar, with a stress increase of 3 bar at the edges of the rupture. Aftershocks were distributedto a broader area as coseismic stress increase affected a 200-km-long section of the western North Anatolian Fault.