Rupture process of the 1999 November 12 Duzce (Turkey) earthquake deduced from strong motion and Global Positioning System measurements

We use the strong motion data recorded at near-fault accelerometers combined with Global Positioning System (GPS) measurements to infer the space and time evolution of the M-w= 7.2 1999 November 12 Duzce (Turkey) earthquake. We confirm that the rupture is subshear towards the west whereas it overpassed the shear speed towards the east. The mechanism of the earthquake is predominantly right lateral on a 65degrees north-dipping fault. The strike-slip we infer represents at least 75% of the total seismic moment. We stress that the use of strong motion data allows us to constrain a strong spatial variation of the slip direction during faulting: to the west of the hypocentral region, the slip is oblique accompanied by a significant normal component. In the central and eastern part of the activated fault the slip is almost pure right lateral. This result is consistent both with the surface offset observations and with the long-term morphology of the fault. Neither strong motion data nor GPS data can resolve the complexity of the eastern termination of the Duzce rupture.