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Zusammenfassung:
Turkey is home to two major fault systems, which make it the most seismically active country in Europe. These are namely the right-lateral North Anatolian Fault (NAF) and left-lateral East-Anatolian Fault Systems (EAF) with lengths of á ∼1500 km and ∼500 km, respectively. They are capable of producing moderate to large earthquakes in given time periods. Starting from the most western point, on 26 September 2019, a sequence of moderate-sized events (Mw 5.8; Mw 4.1 and Mw 4.7) occured on the Main Marmara Fault (westernmost branch of NAFZ). Only 3 years later the central part of the NAF produced (after a silence of 23 years) a Mw 6.0 earthquake close to Düzce province (Gölyaka Earthquake), the region that was hit in 1999 by an Mw 7.2 event that killed more than 700 people. Most recently, the EAF ruptured in three different segments and generated two large earthquakes just within a time-span of 9 hours: Mw 7.8 (Pazarcik Earthquake) and Mw 7.7 (Elbistan Earthquake). The events have killed so far over 45,000 people and are the most destructive earthquakes with the highest death toll in modern times. Based on the dense Turkish seismic network (AFAD-TADAS), we analyze the strong ground motions in terms of their spatial variation and realize azimuthal variations in peak-ground acceleration (PGA) and peak-ground velocity (PGV) with regard to rupture propagation, coupled with evidence of strong velocity pulses. This trend has been interpreted as directivity effects which systematically occur on sites located towards rupture propagation.
