Rupture behavior of the 2020 Mw 6.8 Elazig (Turkey) earthquake and its tectonic implications

Abstract:

This study presents the first characterisation of the 2020 Mw6.8 Elaziğ (Turkey) earthquake that was the largest along the Eastern Anatolian Fault in over a century. The East Anatolian Fault is characterized by a scarcity of large instrumental events compared to the North Anatolian Fault, therefore documenting the mainshock rupture, the relation with previous earthquake and early postseismic deformation are pivotal to gain a better understanding in what drives rupture behavior. We propose an original and comprehensive contribution using geodetic and seismological data, including techniques such as INSAR, elastic dislocation modelling, teleseismic back projections, regional moment tensor analyses, and calibrated hypocentral relocations. The results indicate a mostly westwards rupture propagation from a nucleation point on an abrupt 10° fault bend. The rupture was halted by an established segment boundary at one end. The result also indicate abundant evidence of fault immaturity, such as: pronounced shallow slip deficit not fully recovered through early shallow afterslip, low-to-intermediate structural maturity, slow rupture propagation speed and scattered aftershocks. This is an important result for seismic hazard assessment in this region and depicts the importance of using multiple geophysical approaches.