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- MakaleAçık Erişim2026Seismic potential in and around the Muş basin (Eastern Türkiye): Insights from stress analysis and statistical modeling; [Muş havzası (Doğu Türkiye) ve civarındaki deprem potansiyeli: Gerilme analizi ve istatistiksel modellemeden elde edilen çıkarımlar]
Şimşek, Ecenur Cansu; Alkan, Hamdi; Öztürk, Serkan
In this research, current and near-future potential earthquake zones in and around Muş basin (eastern Türkiye) are investigated using the instrumental period earthquake catalog and focal mechanism parameters of local earthquakes. For this purpose, the relationships between the b-value distributions and the Colulomb stress changes are interpreted with different depth ranges (5 to 25 km). Also, for a reliable prediction, the occurrence probabilities, recurrence periods of earthquakes, and the Z-value distribution (seismic quiescence areas) are taken into consideration. 15,722 earthquakes with moment magnitudes with 0.8≤Mw≤6.9 between the latitudes of 38.2°N-39.6°N and longitudes of 40.0°E-43.0°E, over a period of ~90.63 years between November 12, 1934, and June 30, 2025, are used for all statistical analyses. Completeness magnitude, Mc-value is accepted as 2.5±0.5. The b-value is determined to be 0.780 ± 0.04, which is smaller than the average (b = 1.0). Additionally, twenty local events with magnitudes greater than Mw≥4.8 are selected to image the Coulomb stress changes. The occurrence probabilities of earthquakes with Mw=5.5, 6.5, and 6.9 in 10 years are predicted as ~83%, ~27% and ~15%, respectively. Recurrence periods of events with these magnitudes are estimated as ~13, ~32, and ~63 years, respectively. Large Z-values are detected in the Kargapazarı segment, Bingöl province, and west of the Kulp and Kozluk segments. Additionally, the analyses of b-value and Coulomb stress change used for hazard prediction reveal a decreasing b-value and an increasing stress change around the Karlıova Triple Junction at a depth of approximately 10 km. Finally, these seismotectonic parameters can represent the possible locations for earthquake occurrences in the near future.
- MakaleAçık Erişim2025September 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]
Öztürk, Serkan; Alkan, Hamdi
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.
- MakaleAçık Erişim2023Multiple parameter analysis for assessing and forecasting earthquake hazards in the Lake Van region, Turkey
Öztürk, Serkan; Alkan, Hamdi
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.
- MakaleAçık Erişim2022A Statistical Analysis and Evaluation on the Earthquake Forecasting and Hazard for Lake Van and its adjacent area (Türkiye); [Van Gölü ve Civarı (Türkiye) İçin Deprem Tahmini ve Tehlikesi Üzerine İstatistiksel Bir Analiz ve Değerlendirme]
Ozturk, Serkan; Alkan, Hamdi
In this study, current earthquake hazard is tried to present and earthquake forecasting is made for Lake Van and its adjacent area for the next five years. For this purpose, a statistical analysis is achieved with the concomitant use of the b-value, Z-value, relative intensity (RI) and pattern informatics (PI) data. In addition, for the earthquake forecasting in the intermediate term and hazard, a comprehensive discussion is made with the studies analyzing the different seismological and geophysical variables in literature. The relations between these parameters reveal more accurate and reliable approaches. Consequently, at the beginning of 2022, particularly the areas having small b-value and large Z-value with the hotspots (possible earthquake areas) between 2022 and 2027 from the combined forecast map are determined in and around Muradiye, Çaldıran, Özalp, Van city centre and Gevaş including Çaldıran, Yeniköşk, Erciş and Malazgirt faults with Saray and Van Fault zones.
- MakaleAçık Erişim2021A comprehensive spatiotemporal evaluation of the current earthquake activity in different parts of the Frakull-Durrës fault zone, Albania
Öztürk, Serkan; Ormeni, Rrapo
This study presents a detailed spatiotemporal analysis for the Frakull-Durrës (F-D) fault zone at the beginning of 2020. For this purpose, the most frequently used statistical seismicity parameters such as magnitude completeness, Mc-value, Gutenberg-Richter b-value, recurrence times, annual probabilities and standard normal deviate, Z-value, were mapped. The F-D fault zone was divided into two seismogenic subregions, and Mc-value was taken as 2.5 for both the south and north parts. The b-value was estimated as 0.83 ± 0.06 for the south part and 0.85 ± 0.06 for the north part. b-values for both zones are smaller than 1.0 and these values may be considered to be a larger stress accumulation to build up over time and to be released by the next possible earthquakes. Clear decreasing trends were observed in time variations of b-values before the occurrences of several strong main shocks. Analyses of annual probabilities and recurrence times suggest that the study region has an intermediate/long-term earthquake hazard in comparison to occurrences of strong/destructive earthquakes in the short term. Some anomaly regions of a small b-value and a large Z-value were found along the F-D fault zone at the beginning of 2020: i) among Lushnje-Tirana-Durrës including the middle part of the F-D fault zone, ii) in and around Lezha including the north end of the F-D fault zone. Thus, the combination of regions with the lowest b-value and largest Z-value may supply preliminary results for earthquake hazard, and these regions may be considered to be the most likely regions for future strong/large earthquakes in the F-D fault zone.
- MakaleAçık Erişim2021Statistical behaviours of earthquake occurrences in the Central Anatolian Region of Turkey: region-time-magnitude analyses
Öztürk, Serkan
The main objective of this work is to make detailed region-time-magnitude analyses by describ-ing the statistical behaviours of earthquakes in the Central Anatolian Region of Turkey. In this scope, several seismic and tectonic parameters such as Mcomp, b-value, Dc-value, Z-value, recurrence times and annual probabilities were evaluated. For the analyses, a homogeneous catalogue including 10,146 earthquakes with 1.0 ≤ Md ≤ 5.7 between 30 July 1975 and 29 December 2018 was used and spatio-temporal changes of earthquake behaviours were mapped for the beginning of 2019. Earthquake magnitudes varied from 1.9 to 3.0 on average, and hence Mcomp was considered to be 2.6. The b-value was calculated as 1.26 ± 0.07, and this relatively large value indicates that small-magnitude events are dominant. The Dc-value was computed as 1.31 ± 0.03. This small value means that distances between epicentres approach the diameter of the cluster, and seismic activity is more clustered at smaller scales or in larger regions. The spatio-temporal analyses of recurrence times suggest that the Central Anatolian Region has an intermediate/long-term earthquake hazard in comparison to occurrences of strong earthquakes in the short term. Several anomaly regions of a small b-value and a large Z-value were found in and around the Tuzgölü Fault Zone, Central Anatolian Fault Zone, Salanda fault and Niğde fault at the beginning of 2019. Thus, a combination of the regions with a lower b-value, a higher Z-value and also moderate recurrence times may give significant clues for the future possible earthquakes, and detected regions may be thought to be the most likely areas for strong/large events in the Central Anatolian Region.
- MakaleYalnız künye2020A GENERAL OVERVIEW ON THE REGION-TIME BEHAVIORS OF THE RECENT EARTHQUAKE ACTIVITY IN THE MARMARA REGION OF TURKEY
Öztürk, Serkan; Gerdan, Serpil
The principal aim of this study is to make a general assessment of the regional and temporal behaviors of the seismicity in the Marmara region of Turkey. For this purpose, the well-known spatio-temporal tools such as Mc-value, b-value, Dc-value, Z-value, recurrence period and annual probability were evaluated. The data catalog is homogeneous for local magnitude, ML, and includes 18,662 events with 0.4≤ML≤5.7 between 2000 and 2020. Earthquake magnitudes change between 1.5 and 3.0 and hence, Mc-value was taken as 2.7. b-value was calculated as 1.14±0.07 and the earthquakes with small magnitude can be effective on this relatively large value. Dc-value was estimated as 1.57±0.03 with a scale invariance from 5.03 to 87.64 km. This moderate value means that distance between the epicenters approaches the diameter of cluster and, earthquake activity is more clustered in larger areas or at smaller scales. Time-magnitude estimations of annual probability and recurrence period indicate that the Marmara region has an intermediate/long terms hazard for the occurrence of strong/large earthquakes. Anomaly regions with low b-value and large Z-value observed at the beginning of 2019 can be considered as the most likely regions for strong/large earthquake occurrences in the next. As a remarkable fact, a correlation and combined interpretation of these seismotectonic parameters may supply a preliminary and essential perspective in the seismic hazard for strong/large earthquake occurrences in the Marmara region of Turkey in the intermediate/long terms.
- MakaleYalnız künye2020A study on the variations of recent seismicity in and around the Central Anatolian region of Turkey
Öztürk, S.
Variations of the recent seismicity in and around the Central Anatolian region of Turkey were evaluated based on the seismic b-value, standard normal deviate Z-value, GENAS modelling, annual probabilities and return periods of the earthquakes. The catalog includes 16,702 earthquakes between 1974 and 2019 with magnitudes from 1.0 to 6.3. Time distribution of b-value shows that there is a tendency to decrease after the year of 2002 and b-value decreased from 1.58 ± 0.03 to 1.25 ± 0.05 at the beginning of 2019. Annual probabilities for magnitude ranges of 3.0–4.0 have the values between 3 and 30. Return periods for magnitude levels of 5.0–5.5 have the values from 5 to 20 years, and a value of 80 years for magnitude level of 6.0. The GENAS results show the significant temporal variations in the number of earthquakes smaller and larger than specific magnitude intervals by supplying the beginning periods of increases and decreases in the earthquake activity rate. Remarkable reductions in region-time distribution of b-value at the beginning of 2019 were detected in the regions covering Niğde fault and its vicinity along the south, west, northwest and southwest directions, among the Mut Fault Zone, Karsantı-Karaisalı Fault Zone and Karataş-Osmaniye Fault Zone, in and around Sürgü fault and along its northwest direction, between Sürgü fault and East Anatolian Fault Zone. Significant seismic quiescence areas in Z-value distribution include the northwest ends of the Tuzgölü Fault Zone and study area including Akpınar fault, the northeast of Salanda fault, between Salanda fault and the Central Anatolian Fault Zone, the northeast parts of the Central Anatolian Fault Zone, the west of Malatya fault, between Sürgü fault and the East Anatolian Fault Zone, the southeast end of the Tuzgölü Fault Zone, Karsantı-Karaisalı Fault Zone and its vicinity, the southwest of Tuzgölü. Thus, these anomaly areas observed in the Central Anatolian region and its vicinity at the beginning of 2019 may be one of the most likely zones for the next strong/large earthquake occurrences.
- MakaleAçık Erişim2019Region-Time-Magnitude Analyses of the Seismicity in and around the Central Anatolian Region and Current Earthquake Potential; [Orta Anadolu Bölgesi ve Civarındaki Depremselliğin Bölge-Zaman-Magnitüd Analizleri ve Güncel Deprem Potansiyeli]
Öztürk, Serkan
The purpose of this study is to make detailed statistical analyses of earthquake occurrences in and around the Central Anatolian Region of Turkey and to forecast the possible earthquake regions in the future. In this scope, by performing the region-time-magnitude analyses of seismotectonic variables such as Mc-value, b-value, Dc-value, Z-value, the current/future earthquake potential was defined. b-value was computed as 1.26±0.07 by taking Mc=2.6 and this large value indicates that the earthquakes with small magnitude are dominant. Dc-value was calculated as 1.31±0.03 and this relatively small value shows that distance between the epicenters approaches the diameter of cluster, and earthquake activity is more clustered in larger regions/at smaller scales. Anomaly regions with low b-value and large Z-value at the beginning of 2019 were found in and around Tuz Gölü Fault Zone, Central Anatolian Fault Zone, Salanda and Niğde faults. As an important result, these regions may be considered as the most likely regions for strong/large earthquakes in the future.
- MakaleAçık Erişim2017Space-time assessing of the earthquake potential in recent years in the Eastern Anatolia region of Turkey; [Evaluación espacio-temporal del potencial de terremotos en los años recientes para la región de Anatolia, en el este de Turquía]
Öztürk, S.
In this study, a statistical analysis is carried out to reveal the current earthquake potential in the Eastern Anatolia region of Turkey. For this purpose, a space-time assessing based on the recent changes in Gutenberg-Richter b-value, seismic quiescence Z-value, cumulative moment, annual probability and recurrence time of earthquakes is achieved. Temporal variation of b-value indicates that average b-value decreased from 1.25±0.02 between 2002 and 2010 to 1.08±0.02 between 2011 and 2015. A clear quiescence in the seismic moment in recent years may be a clue foretelling the occurrence of an intense event. Annual probability of the earthquakes between 3.5 and 4.0 magnitude levels exhibits a value equal to and larger than 30. Recurrence time of the earthquakes has a value between 2.0 and 3.0 years for magnitude level of 6.0, and a value between 6.0 and 7.0 years for magnitude level of 7.0. A significant decrease in b-value and clear quiescence anomalies in Z-value at the beginning of 2015 are observed in the several same regions. These areas cover the Central Anatolia Fault Zone, Malatya and Ovacık faults, the southeastern part of the Eastern Anatolia Fault Zone, and the junction of the Eastern Anatolia and Dead Sea Fault Zones. In these anomaly regions, a decreasing trend in b-value may be an indicator of stress increases and an increasing trend in Z-value may show the quiescence areas before the next earthquake occurrences. As a remarkable fact, these areas in the Eastern Anatolia region may be interpreted as one of the most likely locations for the major earthquakes in the future.