Preliminary Results of Dynamic Rupture Simulations of the Mw7.8 Kahramanmaras Earthquake

It is essential to investigate how ruptures develop and propagate dynamically along the East Anatolian Fault (EAF) and what conditions explain the rupture propagation patterns observed for recent earthquakes. The northeast motion of the Arabian plate with respect to the Anatolian microplate and the African plate is accommodated along the left-lateral East Anatolian and Dead Sea faults.  The slip-rate along the northern Dead Sea Fault is about 4 mm/yr while the slip rate along the EAF increases from 5 mm/yr to ~12 mmm/yr towards the northeast where it connects to the North Anatolian Fault. The Mw7.8 Kahramanmaras earthquake on 6^th of February 2023 initiated along a splay called the Narli fault and proceeded along the EAF bilaterally, rupturing a total of more than 300 km. The earthquake ruptured a significant portion of the EAF and a section of the Amanos Fault which connects to the Cyprus Arc offshore. One interesting point is that the rupture along the EAF was dynamically triggered by a splay which is at an acute angle of ~30°. This raises the question of how the slip distribution and rupture parameters were affected by the rupture initiation at a splay fault. Initial models indicate that the rupture propagated faster toward northeast and slower toward southwest, which might indicate that the directivity of the splay fault played an important role in the rupture dynamics of this earthquake. Remarkably, this complex event triggered another destructive earthquake with magnitude Mw7.6, west of the epicenter of the first mainshock, nine hours later. The second event caused a relatively short surface rupture (~80 km) with high stress drop. The analysis of 3D dynamic earthquake rupture simulations contributes to a comprehensive understanding of the effects of material properties and initial stresses on dynamic triggering and ground motion intensity. In this study we will show our preliminary results of the dynamic modeling of the Mw7.8 earthquake using the Finite Element community code Pylith. East and south Anatolia contain many faults which are capable of generating M>7.0 earthquakes in the near future. Therefore, understanding the dynamics of the Kahramanmaras earthquakes and stress transfer to neighboring faults is important in order to understand the potential for new destructive earthquakes in the surrounding area, and to generate scenarios of damage, shaking and PGA distributions.