The North Anatolian Fault Zone (NAFZ) is an intersection area between the Anatolian and Eurasian plates. The Arabian Plate, which squeezes the Anatolian Plate from the south between the Eurasian Plate and itself, is also responsible for this formation. This tectonic motion causes the Anatolian Plate to move westwards with almost a 20 mm yr⁻¹ velocity, which has caused destructive earthquakes in history. Block boundaries that form the faults are generally locked to the bottom of the seismogenic layer because of the friction between blocks and are responsible for these discharges. However, there are also some unique events observed around the world, which may cause partially or fully free-slipping faults. This phenomenon is called “aseismic creep” and may occur through the entire seismogenic zone or at least to some depths. Additionally, it is a rare event in the world located in two reported segments along the North Anatolian Fault (NAF), which are İsmetpaşa and Destek. In this study, we established GPS networks covering those segments and made three campaigns between 2014 and 2016. Considering the long-term geodetic movements of the blocks (Anatolian and Eurasian plates), surface velocities and fault parameters are calculated. The results of the model indicate that aseismic creep still continues with rates of 13.2±3.3 mm yr⁻¹ at İsmetpaşa and 9.6±3.1 mm yr⁻¹ at Destek. Additionally, aseismic creep behavior is limited to some depths and decays linearly to the bottom of the seismogenic layer at both segments. This study suggests that this aseismic creep behavior will not prevent medium- to large-scale earthquakes in the long term.

Bu çalışmada 6 Şubat 2023 tarihinde sırasıyla yerel saat ile 04:17 ve 13:24’te artarda meydana gelen Sofalaca-Şehitkamil Gaziantep (Mw:7.7) ve Ekinözü Kahramanmaraş (Mw:7.6) depremlerinin öncül jeodezik sonuçları verilmiştir. Öncül jeodezik sonuçları elde etmek için deprem odak merkezleri etrafındaki ve etkili olduğu alandaki TUSAGA-Aktif istasyonlarına ait GNSS alıcılarından 30 sn (0,033 Hz) ve 1 sn’lik (1 Hz) GNSS gözlemleri kullanılmıştır. Deprem kaynaklı kosismik yer değiştirmeleri belirlemek için bağıl statik çözümler GAMIT/GLOBK yazılım takımında 30 sn’lik RINEX verileri kullanılarak yapılmıştır. Statik çözümlerde değerlendirmeye alınan istasyonlarda Sofalaca-Şehitkamil Gaziantep depreminde doğu bileşende atımın 1.1-23.4 cm, kuzey bileşende 1.1-30.9 cm aralığında değiştiği görülmüştür. Ekinözü Kahramanmaraş depreminde ise atım miktarı doğu bileşende 1.2-440.4 cm, kuzey bileşende 1.4-69.6 cm aralığında değişmiştir. Kinematik çözümler ise PPP yöntemiyle CSRS-PPP ve PRIDE PPP-AR yazılımları ile 1 sn’lik RINEX verileri kullanılarak elde edilmiştir. Her iki yazılımda seçilen istasyonlardaki deprem anı yer değiştirmeler (deplasman) ve ardışık epok farkları (hız) hesaplanmıştır. Seçilen tüm istasyonlarda hızlar Sofalaca-Şehitkamil Gaziantep depreminde doğu bileşen için 3-12.5 cm/sn, kuzey bileşen için 3.8 - 37.7 cm/sn aralığında; Ekinözü Kahramanmaraş depreminde ise doğu bileşende 3.7-20.5 cm/sn, kuzey bileşende 4.1-20.1 cm/sn tespit edilmiştir. Öncül sonuçların elde edilmesinden sonra bölgenin daha yakından takibi ve yeni noktalarda atımların tespiti için yeni bir GNSS ağı kurulmuştur. Kurulan yeni ağda TÜBİTAK 1002-C Doğal Afetler Odaklı Saha Çalışması Acil Destek Programı çağrısı kapsamında arazi çalışmalarına başlanmıştır.

The North Anatolian Fault Zone (NAFZ) in the north of Türkiye is considered one of the most active faults on earth and have caused many major earthquakes in the last century. Surface ruptures by those earthquakes indicate that this tectonic feature consists of many segments, which reveal different characteristics in terms of geometry and mechanism. NAFZ lies along between Bingöl in the eastern Turkey and Saros Gulf in the west. This study focuses on the central part of the NAFZ between Niksar and Ilgaz provinces. In addition to the main branch, the central section of the NAFZ also contains two sub-branches extending southward: Merzifon-Esençay and Sungurlu Faults. In the literature, there are several studies for the region, however a comprehensive study mainly focusing on the main branch of the NAFZ and its sub-branches along the central NAFZ has not been conducted yet, which would fully reveal the fault mechanism and seismic potential in the region. The aim of this study is to derive an up-to-date high-spa-tial-resolution Global Navigation Satellite Systems (GNSS) velocity field for the central NAFZ and to correlate with the strain accumulations along the faults. Based on this, a high-spatial-resolution GNSS network consisting of 60 sites was established enclosing the central NAFZ. The previously archived GNSS data for the same observation sites were collected from the different studies in the region and a new GNSS campaign measurement was conducted between October 2023 and February 2024. All GNSS data were processed using GAMIT/GLOBK software, and the results indicate the GNSS velocities ranging from 3-30 mm/year and their associated uncertainties of maximum ± 1.5 mm/year with respect to the Eurasian tectonic plate.

The North Anatolian Fault Zone (NAFZ) is one of the most important fault zones of Turkey and the world. It has produced several high magnitude earthquakes that have resulted in massive loss of lives and resources. National and international research on the North Anatolian Fault zone that Turkey resides on have been realized to better understand and predict the earthquakes produced by it. This study focuses on the Çankırı – Bingöl segment of the NAFZ. The aim of this study is to calculate the strain and latent earthquake potential of the studied area. For this purpose, geodetic data coming from several individual projects have been merged. Strain values have been calculated from the combined data and regions on the fault zone, and strain accumulations have been presented graphically. After calculation, Çankırı, Amasya and Kelkit regions were analyzed. The compressional and extensional deformation has been shown in north and south part of Çankırı basin, respectively. Eastern adjacent area of the Çankırı basin, Amasya region, has the primary branch of the NAF and its subbranches. In the Amasya region, the deformation is mostly on the main branch and the earthquake potential has risen to it. The Kelkit Valley has complex structures and inhomogeneous dispersion. Southeastern and Northwestern part of the Kelkit Valley has varied deformation in micro scale. Consequently, the study results indicate that strain accumulation is concentrated on areas such as the Çankırı basin, Amasya region, and various areas in the Kelkit Valley from west to east. Análisis de la Velocidad de Deformación en el Segmento Çankırı-Bingöl de la Falla de Anatolia del Norte, Turquía. ResumenLa Zona de la Falla de Anatolia del Norte (NAFZ, del inglés North Anatolian Fault Zone) es una de las zonas de fallas más importantes de Turquía y del mundo. Esta falla ha generado varios terremotos de gran magnitud que han resultado en pérdidas humanas y de recursos. La investigación nacional e internacional de la Zona de la Falla de Anatolia del Norte, que atraviesa Turquía, se ha realizado con el fin de un mejor entendimiento y predicción de los terremotos que allí se originan. Este análisis se enfoca en el segmento Çankırı-Bingöl de la NAFZ. El objetivo es calcular la tensión y el potencial de terremoto del área de estudio. Con este propósito se recopiló la información geodésica de varios proyectos individuales. Los valores de tensión se calcularon de la información combinada de las regiones que componen la zona de falla y se presentan gráficamente las acumulaciones de tensión. Tras el cálculo de estos valores se analizaron las regiones Çankırı, Amasya y Kelkit. La deformación de compresión y la de extensión aparecen al norte y al sur de la cuenca Çankırı, respectivamente. El área ubicada al Este de la cuenca Çankırı, la región de Amasya, posee la rama principal de la NAFZ y sus subdivisiones. En la región de Amasya la deformación se presenta en la rama principal de la NAFZ, donde se eleva el potencial de movimientos sísmicos. El valle de Kelkit tiene estructuras complejas y dispersión no homogénea. El sudeste y el noroeste del valle Kelkit muestran una deformación variada a microescala. Los resultados de este estudio indican que la acumulación de tensión se concentra en la cuenca Çankırı, la región Amasya y varias áreas del valle Kelkit desde el oeste hacia el este.

This study evaluates the performance of multi-constellation GNSS Precise Point Positioning (PPP) for offshore kinematic observations in the challenging environment of Antarctica using the data collected on a moving ship during the 6th Turkish Antarctic Expedition in 2022. The analysis involved two open-source PPP software solutions, PRIDE PPP-AR, and Ginan, which were used to process GNSS data from both GPS-only and multi-GNSS (GPS, GLONASS, Galileo, BeiDou) constellations. The results indicate that PRIDE PPP-AR generally provided better horizontal and vertical positional accuracy than Ginan software, achieving improvements of up to approximately 33% in height component root mean square error (RMSE) for both constellation solutions. While the mean value of horizontal position differences for PRIDE PPP-AR in multi-GNSS solution was 4 cm, while 5 cm for Ginan. The anticipated advantages of multi-GNSS over GPS-only solutions were not consistently observed for Ginan software in 2D position and height components. However, PRIDE PPP-AR demonstrated improved internal consistency with multi-GNSS solution, achieving an RMSE value of 5 cm for horizontal positioning compared to 6 cm for Ginan. The general results of the study reveal that the PPP technique, which does not require any reference station’s GNSS data, can achieve almost the same accuracy as the differential positioning technique. With this superiority, the PPP technique is an ideal positioning technique, especially in remote marine environments and polar regions, where geodetic infrastructure is inadequate and environmental conditions are difficult