Boğaziçi University

Depression and anxiety are among the most prevalent mental health disorders worldwide, yet existing diagnostic tools do not always align with contemporary classification systems such as the International Classification of Diseases-11 (ICD-11). The study aimed to evaluate the validity and reliability of the International Depression Questionnaire (IDQ) and the International Anxiety Questionnaire (IAQ) in the Turkish population. The primary objectives were to assess the psychometric properties of these new health assessment tools, the only based on the ICD-11, in a culturally diverse setting. Participants were recruited through online survey platforms and university announcements, ensuring a diverse representation of the Turkish adult population. The sample consisted of 2894 individuals (1097 male, 1797 female) aged 18-65, including university students, and community members from various socioeconomic backgrounds. Factor analysis revealed that the IDQ and IAQ maintained their original factor structures, supporting their construct validity. The internal consistency of both the IDQ and IAQ was high, with Cronbach's α coefficients exceeding the threshold of 0.70, indicating acceptable reliability. These tools can be confidently used in both clinical and research settings, facilitating better mental health assessment and intervention strategies in Turkey. The findings suggest that the Turkish versions of the IDQ and the are valid and reliable tools for assessing the severity of depression and anxiety symptoms in Turkish adults. These instruments can support both clinical and research efforts by facilitating early identification of individuals who may benefit from further psychological evaluation.

Earthquake early warning has been a longstanding effort of the Kandilli Observatory and Earthquake Research Institute (KOERI), beginning in 1998 with the establishment of the Istanbul Earthquake Rapid Response and Early Warning System. Building on this experience and benefiting from advances in seismic instrumentation and data transmission technologies, KOERI has recently developed a new-generation early warning system(EEWS) that is currently operational across Türkiye; however, given the high seismic hazard associated with the North Anatolian Fault and its offshore segments in the Sea of Marmara, the present current station density, spatial coverage, and communication latency characteristics, the generation of reliable and timely public warning messages is presently feasible primarily in the Marmara region.Earthquake detection, location, and magnitude estimation are performed using the Virtual Seismologist algorithm developed within the TRANSFORM project (funded by the European Union under project number 101188365; Cua, 2005; Cua and Heaton, 2007; Cua et al., 2009). Alerts are issued once seismic signals are recorded at a minimum of four stations. System performance is evaluated using the 2 October 2025 Mw 5.0 Marmara Sea earthquake as a case study. The first early warning alert was issued 8.4 s after the earthquake origin time, providing more than 20 s of warning for the Anatolian side of Istanbul prior to the onset of strong ground shaking. The installation of real-time seafloor seismic stations in the Sea of Marmara is therefore expected to substantially reduce detection times and further enhance the overall effectiveness of the Earthquake Early Warning System (EEWS) in the Marmara Region. These results demonstrate the capability of the KOERI-EEWS to deliver timely alerts and highlight its potential to enhance seismic risk mitigation and the protection of critical infrastructure.

We investigated the geometry and the kinematics of the Sındırgı fault, which was activated during the two M6+ earthquakes (10.08.2025 and 27.10.2025) and their aftershocks. We analyzed all available seismographs from KOERI (Kandilli Observatory and Earthquake Research Institute) and AFAD (Disaster and Emergency Management Authority) to identify fault geometry, earthquake locations, and focal mechanisms. We analyzed P-wave initial polarities and arrival times of a total of 43 M4+ earthquakes including two mainshocks (waveforms from KOERI and AFAD). Fault plane solutions as well as the accurate hypocenter locations indicate that the majority of the mainshocks and the aftershocks activated a south dipping fault. The results indicate an average strike of 110 ± 5.6°, a dip of 61.6 ± 4.4°, and rake a rake -124.6 ± 2.3°. Additionally, we investigated inter-seismic slip rates using 2D dislocation model analyzing the GNSS velocity field. We transformed the most recent velocity field into Anatolian-fixed reference frame. We decomposed GNSS velocities into fault-parallel and fault-perpendicular components and applied 2D arctan curve fitting to simultaneously determine the slip rates and the fault locking depths. Bootstrap error analysis was performed (1σ) to assess error bounds. The lateral motion is nearly negligibly small; however, fault-perpendicular velocities indicate the extension along the Sındırgı fault at 2.34 ± 0.69 mm/y slip rate. Inter-seismic slip rates suggest a rake of -95.2°, a nearly pure normal fault, which is consistent with average mainshock-aftershock rakes. In this context, GNSS-derived interseismic slip rates are capable of forecasting the extensional kinematics of the Sındırgı fault that generated two predominantly normal-faulting M 6+ earthquakes in 2025.

Active continental extension in the western Anatolia-Aegean (since approximately 25 Ma) drives exhumation of several metamorphic core complexes, low angle normal (detachment) faulting, and NE-SW and NW-SE trending strike-slip tectonics. However, the causative relationships among these processes and structures remain poorly understood. Here, we use 3-D thermomechanical numerical models to investigate how strain localization evolves in a stretching continent with plate rotations along a vertical axis. Namely, we test the obliquity of extension between 15° and 60°, the extension velocity of 1–2 cm/yr applied at the plate boundary, an initial crustal thickness of 50 km and a lithospheric thickness of 130 km, as well as the temperature gradient. To characterize the geometry of the fault systems, we calculate the Regime Stress Ratio (RSR) from the stress tensor and evaluate it in regions of high strain rate. We reconcile our model results with up-to-date structural features, including velocity fields from GPS, InSAR data, seismic receiver functions, and regional earthquake datasets from various sources. Preliminary results show that obliquity angle and initial layer thicknesses are first order parameters controlling strain localization, while simultaneously generating significant conjugate strike-slip tectonics. This is in accord with the formation of NE-SW and an array of NW-SE trending faults and clustering of earthquakes (relocated between 2010–2025) along the boundaries of the Gediz, Büyük Menderes and Simav grabens. These findings provide a modeling framework that links fault geometries, metamorphic core complex exhumation, and strike-slip deformation to the extensional tectonics and deeper lithospheric structure beneath the region.