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• MakaleYalnız künye2026/r/gumushane/10534
  Tomography of the source zone of the February 6, 2023, Kahramanmaras, Earthquake Doublets of Southern Anatolia

  Salah, Mohamed K.; Alkan, Hamdi; Öztürk, Serkan; Güney, Recep

  On February 6, 2023, two destructive earthquakes and many posterior aftershocks hit the Kahramanmaras,area in southern Anatolia. The Kahramanmaras, earthquake sequence (KMES) caused extensive damage and economic losses in T & uuml;rkiye and Syria. In this study, the 3-D crustal seismic velocities surrounding the hypocentral region of the KMES are determined using a large dataset of body wave arrival times obtained from local earthquakes. To better constrain the physical properties and seismogenic behavior of the KMES source region, the Vp/Vs ratio is calculated and correlated with Poisson's ratio using the obtained velocity models. To gain a better understanding of the stress conditions and regional earthquake activity in the study area, the depth variation of the b-value is also examined. The velocity structure is generally heterogeneous with both low and high velocities at upper crustal depths. Along the East Anatolian Fault Zone and its environs, low-velocity anomalies are charted. Also, small b-values (<1.0) are estimated in the region encompassing the KMES, especially at upper crustal depths. The KMES source zone is characterized by low b-value, low to average Vp, low Vs, and average/high Vp/Vs ratios. Hit count rates and the resolution test show that the mapped velocity anomalies are robust down to a depth of 45 km. Therefore, the moderate/high Vp/Vs and small b-values at the upper and middle crustal depths along the EAFZ may give constraints on the next earthquake hazards of the study region. The present findings provide deeper insight into the physical properties and the seismogenic potential of the crustal zones in proximity to the active fault segments of the Anatolian Plateau and the northwestern part of Arabia.

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• MakaleAçık Erişim2026/r/gumushane/19401
  Avoidance of Volunteering in Disasters Scale: A Scale Development and Validity Study (Methodological Study)

  Öztürk, Serkan; Demirbilek, Ömer

  Objective: Volunteers are a critical resource in disaster preparedness and response. This study aims to develop a valid and re liable measurement tool that can assess the reasons behind university students’ reluctance to volunteer in disaster situation. Material and Methods: The study was conducted using an exploratory sequential mixed method design. As a result of the thematic analysis of the semi structured interviews, seven themes were identified, and 81 items were formed. The items whose content validity was evaluated with the Law she technique were reduced to 64 and tested in a pilot study and nec essary adjustments were made. The final scale was applied to a sample group of 731 people who met certain criteria. The data were analyzed using SPSS 25.0 and AMOS 24.0 programs. Results: The scale was found suitable for factor analysis according to Kaiser-Meyer-Olkin (>0.60) and Bartlett’s test (p<0.05) results. As a result of exploratory factor analysis, 32 items with low factor loadings (<0.33) and over lapping content were eliminated; confirmatory factor analysis con firmed the structure of the scale consisting of 6 factors and 31 items. The fit indices (χ²/df=3.069, Comparative Fit Index=0.933, Goodness of Fit Index=0.893, Incremental Fit Index=0.933, Tucker-Lewis Index=0.925, root mean square error of approximation=0.053) were found to be acceptable. The Cronbach alpha value of the scale was 0.92 in total and ranged between 0.75 and 0.93 for the sub-dimensions. Conclusion: The developed scale stands out as a valid and reliable tool for assessing university students’ reluctance towards disaster vol unteering.

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• MakaleAçık Erişim2026/r/gumushane/19341
  Orta Anadolu’da Manyetik Anomaliler, Volkanizma ve Depremsellik İlişkilerinin Jeofizik Analizi

  Öztürk, Serkan; Dolmaz, M.Nuri; Kayin, Sercan

  Orta Anadolu, aktif tektonik deformasyon ile volkanik faaliyetlerin birlikte gözlendiği önemli bir jeodinamik bölgedir. Bu çalışmada, Tuz Gölü Fay Zonu ve çevresindeki manyetik anomaliler, derin kabuksal yapılar ve depremsellik arasındaki ilişkiler bütüncül bir yaklaşımla araştırılmıştır. Bu amaçla NOAA tarafından geliştirilen EMAG2-v3 aeromanyetik veri setine Kutba İndirgeme (RTP), Analitik Sinyal (AS) ve Birinci Düşey Türev (FVD) filtreleri uygulanmış, manyetik kaynak derinlikleri hesaplanmıştır. Bölgenin güncel sismotektonik özelliklerini değerlendirmek amacıyla 1900–2026 yılları arasında meydana gelen lokal magnitüdü ML≥3.0 depremler kullanılarak Gutenberg–Richter büyüklük-frekans ilişkisi, b-değeri dağılımı ile deprem episantr ve odak derinliği analizleri gerçekleştirilmiştir. Sonuçlar, yüksek manyetik gradyan zonlarının özellikle Tuz Gölü Fay Zonu ve volkanik merkezler boyunca yoğunlaştığını, manyetik kaynak derinliklerinin yaklaşık 1.3–9.7 km arasında değiştiğini ve deprem odaklarının büyük ölçüde 5–15 km derinlik aralığında kümelendiğini göstermektedir. Ayrıca yüksek manyetik gradyan zonları, düşük b-değeri alanları (1.0<) ve deprem kümeleri arasında genel bir mekânsal uyum belirlenmiştir. Elde edilen bulgular, Orta Anadolu'daki aktif fay sistemleri, volkanik yapılar ve derin kabuksal süreksizliklerin birlikte değerlendirilmesinde manyetik yöntemlerin önemli bir tamamlayıcı araç olduğunu ve bölgenin tektonik ile magmatik evriminin anlaşılmasına katkı sağladığını ortaya koymaktadır.

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• MakaleAçık Erişim2026/r/gumushane/12244
  Seismic 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.

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• MakaleYalnız künye2026/r/gumushane/10368
  Spatio-Temporal Distributions of Seismicity, Stress Evolution, and Tectonomagmatic Signatures of the 2025 Sındırgı Earthquake Swarm, Western Anatolia, Türkiye

  Büyüksaraç, Aydin; Senkaya, Mustafa; Alkan, Hamdi; Bektas, Ozcan; Öztürk, Serkan; Pirti, Atinc; Yücel, Mehmet Ali

  The Simav Fault Zone (SFZ) in Western Anatolia remains one of the most active tectonic regions in Turkey, and the 2025 S & imath;nd & imath;rg & imath; earthquake swarm has renewed concern regarding evolving seismic hazard. This study analyzes the swarm on the S & imath;nd & imath;rg & imath; Segment using Coulomb stress modelling, spatial distributions of b- and p-value, gravity and magnetic anomalies, geothermal data, and GNSS observations. Coulomb stress calculations show that the M-W = 6.1 and M-W = 6.0 mainshocks produced stress increases of similar to 0.1 bar that effectively loaded adjacent segments of the SFZ, D & uuml;vertepe Fault Zone (DFZ), and Gelenbe Fault Zone (GFZ), guiding the east-southeast and northward migration of aftershocks. Spatial statistics indicate a b-value ranging from 0.6 to 1.3 and a p-value between 0.3 and 1.0. The lower b-values (< 1.0) and p-values (< 0.5) mark high-stress regions near the mainshock, and higher values characterize more stable zones. Gravity anomalies delineate a dense volcanic-ophiolitic body in the southwest and a caldera-like depression south of the SFZ, while magnetic anomalies highlight the structural continuation and interaction of the SFZ with the GFZ. GNSS stations recorded centimetre-to millimetre-scale motions: BAL1 moved similar to 1.34 cm horizontally with minor uplift, DEI1 experienced similar to 1.12 cm displacement with small vertical fluctuations, and KIKA shifted similar to 0.85 cm southwestward with largely stable elevation. Together, these results show that the 2025 swarm was controlled by stress transfer within a mechanically heterogeneous tectonomagmatic system. The identified stress-enhanced corridors along the SFZ and DFZ may act as future nucleation zones, emphasizing the need for sustained monitoring of this evolving fault network.

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• MakaleAçık Erişim2025/r/gumushane/14145
  Spatial and temporal analysis of seismicity and seismotectonic parameters in Albania region

  Ormeni, Rrapo; Öztürk, Serkan; Silo, Erald; Bozo, Rrezart; Hoxha, Ismail; Mucaj, Dionald

  A comprehensive analysis of b-value for the Albanian earthquakes was conducted using the instrumental earthquake catalogue of Albanian region. A total of 38,816 seismic events with magnitudes ML> 0.1 on the Richter scale were utilized. Statistical characteristics of the seismicity were examined based on b-value, as defined by the Gutenberg-Richter law. Considering the magnitude completeness (Mc-value) as 2.7, b-value was estimated as 1.09 ± 0.08 and it indicates a normal stress regime in the region. The Mc-value varies from 1.5 to 3.4, and spatial distribution of b-value ranges from 0.79 to 1.16. Higher b-values (> 1.0) were detected in the southernmost part of Albania, whereas lower b-values (< 1.0) were found in the western part, particularly within the Adriatic-Ionian fault zone and the Lushnje-Elbasan-Dibër transversal fault zone, as well as in the south-eastern Leskovik-Erseka-Korça fault zone. Regions with lower b-values correspond to areas with larger-magnitude events, while higher b-values are associated with smaller earthquakes. These findings suggest that b-values across Albania generally round 1.0, with lower values indicating moderate stress accumulation in the western region and within two other active seismic belts. The b-values less than 1.0 may signal areas of increased seismic potential. The occurrence probability of earthquakes across varying magnitudes was found to be very high (99%-100%) for seismic events with ML between 0.5 and 4.5, and lower (less than 95%) for events with ML > 5.5; it varied from 1% to 60% for events with larger ML > 6.0 for different Tr values. Recurrence periods for smaller magnitudes are relatively short (less than 1 year for magnitudes from 1.0 to 4.2), whereas for larger magnitudes (5.0 to 6.0), recurrence periods are longer, about 100 years. The Albanian region is characterized by a complex geological setting and significant seismic activity, and, thus, it can be stated that these types of analyses may be important in terms of seismotectonic evaluation and seismic hazard.

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• MakaleAçık Erişim2025/r/gumushane/14062
  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]

  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.

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• Kitap BölümüYalnız künye2025/r/gumushane/12377
  Seismological Aspects of Doublet Earthquakes Mw 7.8, and Mw 7.6, 6th February 2023, Türkiye/Syria Earthquake and Its Aftershocks: Causes and Consequences

  Polat, Orhan; Ozer, Caglar; Ozturk, Serkan

  Two devastating earthquakes occurred on the Eastern Anatolian Fault Zone (EAFZ), measuring 7.8 and 7.6 moment magnitudes (Mw), struck Türkiye and Syria on February 6, 2023. The first earthquake Mw7.8 took place on the EAFZ in Pazarcik district of Kahramanmaras city and the second earthquake (Mw7.6) was on Cardak Fault (CF, an E-W aligned segment of the EAFZ) in Elbistan district of the same city. The first earthquake on EAFZ and the second earthquake on CF reveal dominant sinistral strike-slip character according to focal mechanisms solutions of aftershocks (e.g., Mw = 6.8, Mw = 6.4). Total number of aftershocks exceeds 58,000 as of November 2023. Destructive earthquakes have resulted significant impact on 11 cities in Türkiye and 5 provinces in Syria. Doublet earthquakes (compound earthquake) and aftershocks have caused remarkable surface rupture that exhibit horizontal and vertical slips along NE-SW oriented EAFZ (400 × 40 km2) and E-W aligned CF (250 × 40 km2). Based on the seismicity analysis, 88% (45 events over 51 of the aftershocks with magnitudes greater or equal to 5.0 occurred within the first three days following the Mw = 7.8 mainshock. The state of stress from 1977 to the Kahramanmaras doublet earthquakes (DEQ), was almost shear stress regime whereas it reveals between extension (normal) to strike-slip regime. The CF zone area exhibits a dominant shear stress regime. The Kahramanmaras earthquake has generated remarkable set of surface ruptures about ~ 500 km, in total (~ 350 km long for EAFZ and ~ 150 km for CF) with a dominant sinistral strike-slip character. These ruptures could be observed mainly from the south of Hatay city up to north of Celikhan district along the EAFZ, and between Goksun district and Kelhalil village along the CF. Seismic gaps with low geodetic strain rates and low background seismicity were observed between Islahiye (Hatay city) and Nurdagi (Gaziantep city) districts, and around Pazarcik district (Kahramanmaras city). The largest peak ground acceleration (PGA) was recorded by Pazarcik station (Code: 4614) with about 2 g (2039 gal) in the EW component. The next target location for destructive earthquake could be on the Cyprus arc towards Island with the potential to cause a tsunami, or could occur along the DSF by affecting Syria and Lebanon. The EAFZ is an important reminder that large faults can generate very large earthquakes on multiple segments as Türkiye and Syria have experienced during and after the Mw = 7.8 mainshock.

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• MakaleYayıncıda açık erişim2025/r/gumushane/12339
  Statistical and seismotectonic analyses of the Marmara region under existing stress regime in the west of the NAFZ

  Alkan, Hamdi; Öztürk, Serkan; Bektaş, Özcan; Büyüksaraç, Aydın

  The Marmara Region is an active tectonic region in northwestern Türkiye, which comprises some important strike-slip active fault mechanisms and important tectonic units, located near the western part of the North Anatolian Fault Zone. In the historical and instrumental period, the Marmara Region experienced large/devastating earthquakes. Considering this continuous activity, in this study, we investigate the tectonic structure and performed future seismic hazard estimation of the region based on some seismotectonic parameters. For this evaluation, we plot the Coulomb stress change maps of 1912 Mürefte-Şarköy, 1953 Yenice-Gönen and 1999 İzmit mainshocks with the earthquakes (MW ≥ 4.5) that occurred in the study region after 2003. For the estimation of b-value, occurrence probabilities and return periods of earthquakes, we used a homogenous local seismicity catalogue consisting of 119.029 events for the period between 1912 and 2023. In the findings of this study, the lower b-values and increasing Coulomb stress changes which are trigger stress failure compatible are observed in the west and northwest of the Marmara Sea. In contrast, the higher/moderate b-values and decreasing Coulomb stress values are observed in the east and southeast of the Marmara Sea. The results of probability assessments show that an earthquake with Mw = 6.5 may occur with a probability of 98% in the west of the Marmara Sea after 2025. As a remarkable fact, a comprehensive assessment of these types of variables will supply important findings for earthquake hazard and potential in the study region.

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• MakaleYalnız künye2025/r/gumushane/12103
  A Comprehensive Assessment for the Aftershock Sequence of August 11, 2012 Varzaghan-Ahar Doublet Mainshocks, NW Iran

  Öztürk, Serkan; Yaghmaei-Sabegh, Saman

  In this study, an evaluation of regional, temporal and magnitude properties of the August 11, 2012 Varzaghan-Ahar aftershock sequence was performed based on the different variables such as the Gutenberg-Richter b-value, the Modified Omori p-value, fractal dimension Dc-value and the maximum aftershock magnitude Mamax value which commonly used to describe aftershock behaviors. b-value was computed as 0.73 ± 0.03 for the study area where catalog has a completeness magnitude Mc = 2.0. This b-value is relatively small from typical b≈1 and it can be due to the abundance of aftershocks larger than Mw = 4 in the region. Structural heterogeneity of the seismic source along with the compressive stress situation of the aftershock area could be another reason for this finding as well. p-value was estimated as 1.00 ± 0.03 where c-value took 0.342 ± 0.106 according to the analysis which shows that the number of aftershocks of the Varzaghan-Ahar mainshock shows a relatively fast decrease. Dc-value was computed as 1.84 ± 0.07. This large value indicates homogeneously distributed aftershocks and more clustering in smaller areas or larger scales. As a result, the smallest b-values (< 0.7) and Mamax values larger than 5.0 were obtained around the mainshock. In addition, the biggest p-values (> 1.2) were found in and around the mainshock including Varzaghan. The areas having the biggest p-value and the lowest b-value have great coseismic deformation and stress, respectively. Hence, we can say that coseismic deformation and stress distributions are very effective on the b- and p-value changes. Thus, particular attention on assessing the aftershock hazard may be directed on the understanding of these spatio-temporal aftershock variables.

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