Browsing by Author "Öztürk, S."

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Analyzing the October 16, 2024 Mw 5.9 Kale (Malatya) Earthquake in Relation To the February 2023 Kahramanmaraş Earthquake Sequence and Local Tectonic Dynamics
(Springer Science and Business Media Deutschland GmbH, 2025) Senkaya, M.; Alkan, H.; Öztürk, S.; Büyüksaraç, A.
The 6 February 2023 Mw 7.7–7.6 Kahramanmaraş earthquake sequence has significantly impacted the East Anatolian Fault zone, including the city of Malatya and its immediate surroundings. In addition to the aftershocks of February 2023, the Mw 5.9 Kale earthquake that occurred on October 16, 2024, further underscores the ongoing seismic activity in the region. This study analyzes the distribution of b-values derived from a comprehensive dataset comprising 14,549 earthquakes and the Coulomb stress variations associated with the aftershocks of the February 2023 sequence and the Kale earthquake. The primary objective of this analysis is to enhance the understanding of the tectonic setting that contributed to the occurrence of the Kale earthquake. The findings indicate that the low b-values and stress transfer through the Pütürge segment toward the unnamed fault near Kale are significant contributing factors to the occurrence of the Kale earthquake. Additionally, positive stress variations from Doğanşehir to Malatya’s city center suggest a potential fault oriented toward the city center that may increase the current earthquake hazard. Furthermore, the distribution of seismic events around Malatya suggests a possible barrier supported by previous magnetic data analysis between Malatya and Kale. Lastly, the observed stress variations for the Kale earthquake indicate the likelihood of upcoming seismic events in both the northeast and southwest directions of the Kale. © The Author(s) 2025.
Multiple Parameter Analysis for Assessing and Forecasting Earthquake Hazards in the Lake Van Region, Turkey
(Nature Research Centre, 2023) Öztürk, S.; Alkan, H.
A detailed spatial-temporal analysis of the seismic activity in and around the Lake Van region was performed using several seismotectonic parameters such as b-value, Z-value, relative intensity (RI), pattern informatics (PI), and Coulomb stress changes. Correlations between these parameters were analyzed to esti-mate and forecast potential seismic hazards in the Lake Van region. Particular attention was paid to the parts of the study region that exhibited smaller b-values, higher Z-values, and high-stress changes at the beginning of 2022 and to the locations of earthquake hotspots determined from the composite earthquake forecast map for 2022–2032, i.e., Muradiye, Çaldıran, Özalp, Erçek, Van city center and Gevaş covering the faults of Çaldıran, Yeniköşk, Erciş, Malazgirt and the fault zones of Saray and Van. To provide more accurate interpretations regarding potential earthquake occurrences in the near future, the seismotectonic parameters analyzed in the scope of this study were compared with the corresponding seismological, geological, geodetical, and geochemical variables reported in the literature. This comparison showed that, firstly, our results are consistent with those reported in previous studies, and, secondly, all these variables should be interpreted in combination to correctly assess strong earthquake hazards. Furthermore, this type of multiple-parameter analysis may be important for the description of seismic, tectonic, and structural characteristics of the nature of the crust. Our findings show that almost all seismotectonic parameters indicative of anomaly regions, i.e., lower b-values, higher Z-values, high-stress distribution, and hotspots, were recorded in the same parts of the study region. Thus, the anomaly regions detected at the beginning of 2019 and between 2022 and 2032 may be considered to be potential zones of future great earthquakes. To summarize, the correlations among these variables may provide accurate information for assessing and forecasting earthquake hazards in this region. © Baltica 2023.
September 25, 2024 Yumrukaya-Tatvan (Bitlis, Türkiye) Earthquake and a Seismo-Tectonic Evaluation of Its Impact on the Earthquake Hazard in the Region; 25 Eylül 2024 Yumrukaya-Tatvan (Bitlis, Türkiye) Depremi ve Bölgedeki Deprem Tehlikesine Etkisi Üzerine Sismo-Tektonik bir Değerlendirme
(Gumushane University, 2025) Öztürk, S.; Alkan, H.
The current and future earthquake hazard in and around Bitlis were tired to reveal by utilizing the September 25, 2024, Yumrukaya-Tatvan earthquake (Mw=4.5) and its aftershocks, b-value and Z-value distributions, occurrence probabilities and recurrence periods of earthquakes and variations in Coulomb stress within the scope of this study. Also, it was tried to determine which fault systems in the study area is related to the Yumrukaya-Tatvan mainshock, characterized by strike-slip faulting. b-value in G-R relation was computed as 0.84∓0.06 and small b-values (<1.0) were imaged in the north-northwest-southeast directions throughout the South East Anatolian Thrust Zone and Muş Fault Zone, and west of Lake Van. At the beginning of 2025, significant seismic quiescence was observed near the Muş Fault Zone and the south and southeast of the South East Anatolian Thrust Zone. Recurrence periods for the events with the magnitudes of Mw=5.0, 5.5 and 6.2 were computed as ~10, ~26 and ~100 years, respectively. Additionally, occurrence probabilities of earthquakes with these magnitudes in the intermediate-term (~10 years) were calculated as ~64%, ~32% and ~10%, respectively. Positive Coulomb stress changes carry out a movement from the Kavakbaşı Fault zone in the west and the Beğendik segment in the east toward the South East Anatolian Thrust Zone in the east-southeast. In this region, there is no active fault/fault system according to the General Directorate of Mineral Research and Exploration. Thus, these findings are significant clues showing that multiple parameter seismo-tectonic analyses are important in determining the earthquake hazard for the September 25, 2024 earthquake, and that regions with small b-values and seismic quiescence and regions with positive Coulomb stress changes may indicate current hazard and possible earthquake zones in the future. © 2025 Elsevier B.V., All rights reserved.