The 2020 Mw 6.8 Elazığ earthquake was the largest along the East Anatolian Fault (EAF) in over a century, providing valuable insights into its rupture behavior. We use satellite geodesy and seismology to detail the mainshock rupture, postseismic deformation, and aftershocks. The mainshock propagated mostly westward at ∼2 km/s from a nucleation point on an abrupt ∼10° fault bend. Only one end of the rupture corresponds to an established EAF segment boundary, and the earthquake may have propagated into the slip zone of the 1874 M ∼ 7.1 Gölcuk Gölu earthquake. It exhibits a pronounced (∼80%) shallow slip deficit, only a small proportion of which is recovered by early aseismic afterslip. The slow rupture velocity, shallow slip deficit, and minimal afterslip are characteristic of earthquakes hosted by faults of low‐to‐intermediate structural maturity, indicating that faults continue to evolve in important ways even as they accrue cumulative offsets of tens of kilometers.
The European Integrated Data Archive (EIDA) is the infrastructure that provides access to the seismic-waveform archives collected by European agencies. This distributed system is managed by Observatories and Research Facilities for European Seismology. EIDA provides seamless access to seismic data from 12 data archives across Europe by means of standard services, exposing data on behalf of hundreds of network operators and research organizations. More than 12,000 stations from permanent and temporary networks equipped with seismometers, accelerometers, pressure sensors, and other sensors are accessible through the EIDA federated services. A growing user base currently counting around 3000 unique users per year has been requesting data and using EIDA services. The EIDA system is designed to scale up to support additional new services, data types, and nodes. Data holdings, services, and user numbers have grown substantially since the establishment of EIDA in 2013. EIDA is currently active in developing suitable data management approaches for new emerging technologies (e.g., distributed acoustic sensing) and challenges related to big datasets. This article reviews the evolution of EIDA, the current data holdings, and service portfolio, and gives an outlook on the current developments and the future envisaged challenges.
21 March 2018 in Geophysical Journal International
The 2017 July 20 Bodrum–Kos earthquake (Mw 6.6) is the largest instrumentally recorded earthquake in the Gökova graben, one of the primary physiographic features of SW Turkey. Using seismology and satellite geodesy, we investigate its source characteristics, aftershock distribution, relationship with earlier instrumental seismicity, and association with known surface faulting. We show that the earthquake ruptured a planar (non-listric) normal fault that dips gently (∼37°) northwards beneath the northern Gulf of Gökova coastline, initiating at a depth of ∼11 km and rupturing upwards and bilaterally. Aftershocks concentrate around (but not necessarily on) the western, eastern and downdip edges of the ∼25 km-long rupture plane, and have maximum focal depths of ∼15 km. The main shock surface trace bounds a bathymetric ridge east of Kos island, and may be one of the several faults imaged previously in this area using seismic profiling and multibeam sonar. The fault thus lies within the hangingwall of the lower-angle (∼20° N-dipping) South Datça fault, which it presumably cross-cuts at depth. Through calibrated relocations, we confirm that sequences of moderate (Mw 5–5.5) earthquakes in 1989, 2004 and 2005 occurred in the eastern and central Gulf of Gökova, many of them likely within the hangingwall of the S-dipping Gökova fault. Overall, our results indicate a switch from dominant S-dipping normal faulting in the eastern graben to dominant N-dipping faulting in the west, but we find no support for a proposed NE–SW-trending left-lateral fault in the central Gulf; most colocated focal mechanisms involve ∼E–W normal faulting. Finally, the Bodrum–Kos main shock adds to growing set of examples from across the Aegean region of large normal faulting earthquakes that cut the seismogenic layer as simple planar structures.
Turkey is located in a seismically active region with a complex tectonic history. In order to perform seismic risk assessment precisely, major fault zones (North Anatolian Fault Zone and East Anatolian Fault Zone) that are well defined are monitored continuously. It is a widely known fact that intraplate settings, such as Anatolian Plate, in which devastating earthquakes may occur, need to be observed densely. In this study, we investigate the seismotectonics of Malatya Fault within the Malatya Ovacık Fault Zone (MOFZ), which is one of the major agents responsible for internal deformation acting on Anatolian Plate. Recent geological and paleoseismological studies underline the necessity of comprehending the seismicity and latency of a major earthquake in this fault zone.We applied traditional techniques to investigate data of such a region. Earthquakes that occured in the vicinity of Malatya Fault between the years 2011 and mid-2019 are employed in a detailed analysis. The results of this study are constrained by the distribution of sensor networks in the region, yet allowing to define an active structure which is not included in the active fault map of Turkey, therefore, making a significant contribution to seismic hazard estimation.
Major funding was provided by the UK Natural Environment Research Council (NERC) under grant NE/I028017/1 and partially supported by Boğaziçi University Research Fund (BAP) under grant 6922. We would like to thank all the project members from the University of Leeds, Boğaziçi University, Kandilli Observatory, Aberdeen University and Sakarya University. I would also like to thank Prof. Ali Pinar and Dr. Kıvanç Kekovalı for their valuable comments. Some of the figures were generated by GMT software (Wessel and Smith, 1995).Peer reviewedPostprin
Summary. We present the analysis of a Love-wave dispersion study performed across Turkey and the surroundings. Group velocity dispersion curves were obtained f