Hakan Yavasoglu

GPS Measurements along the North Anatolian Fault Zone on the Mid-Anatolia Segment

The North Anatolian Fault (NAF) is one of the longest active strike slip systems. Slip rate of the NAF was estimated from the GPS data as 20–24mm/yr approximately from previous studies. One of the important features of the NAF is seen in the central part. Here NAF consists of southward splitting concave branches. These splines generally have right-lateral slip and can be compared with Riedel fractures. The important splays are Sungurlu, Merzifon and Lacin faults. A new project “Determination of Kinematics along the North Anatolian Fault Branch between Ladik and Ilgaz with GPS Measurements”, founded by The Scientific and Technical Research Council of Turkey (TUBITAK) and Istanbul Technical University (ITU) Research Fund has been carried out in order to determine the magnitude and direction of the block movements in the region by using GPS since 2001. The knowledge about the neotectonics of the region with the contributions of geology and seismology after the GPS campaigns is expected to provide further information on the assessment of the earthquake potential.

Slip distribution and source parameters of the 20 July 2017 Bodrum-Kos earthquake (Mw6.6) from GPS observations

Abstract Greek-Turkish boundary near the cities Kos and Bodrum has been shaken on July 20, 2017 by a Mw6.6 earthquake. The mainshock is located offshore and did not generate an on-land surface rupture. Analyzing pre- and post-earthquake continuous/survey-type static GPS observations, we investigated co-seismic surface displacements at 20 sites to characterize source parameters and slip-distribution of the mainshock. Fault plane solutions as well as co-seismic slip distribution have been acquired through the inversion of co-seismic GPS displacements modeling the event as elastic dislocations in a half space. Fault plane solution shows a southward dipping normal-type fault segment extending a depth down to ~12 km, which remains within the brittle upper crust. Results from the distributed slip inversion show that the mainshock activated a ~65 km fault section, which has three high slip patches, namely western, central and eastern patches, where the coseismic slips reach up to 13, 26, and 5 cm, respectively. This slip pattern indicates that the pre-earthquake coupling, which is storing the slip deficit, occurred on these three patches.

Monitoring of Deformations Along Fethiye-Burdur Fault Zone (Turkey) with GPS

Afyonkarahisar, Burdur and Fethiye region, southwest of Turkey is located on a tectonically active area. According to the historical recordings, the region was destructed by earthquakes many times. Since the beginning of the 20th century, more than 35 earthquakes with magnitudes bigger than 4 occurred in Afyonkarahisar region. Seven earthquakes recorded over the last 90 years in the region between Burdur and Fethiye whose magnitudes are between 5.0 and 7.0. This new project “Monitoring of Deformations Along Fethiye-Burdur Fault Zone With GPS”, is founded by The Scientific and Technical Research Council of Turkey (TUBITAK), Istanbul Technical University (ITU), Karadeniz Technical University (KTU) and Afyon Kocatepe University (AKU). The aim of the project is to determine strain accumulation of the study area.

Monitoring the deformation and strain analysis on the Ataturk Dam, Turkey

ABSTRACT Every man-made structure creates certain risks — dams are no exception. Most failures in man-made structures that have occurred could have been avoided if the structures’ behaviour had been inspected, monitored, and analyzed continuously, and if proper corrective measures had been taken in a timely fashion. The DSI (The General Directorate of State Hydraulic Works), which is the institution responsible for dam safety, has long used surveying methods to measure the displacements of geodetic points as a part of dam monitoring policy. In this study, we focus on the dams mechanical behaviour throughout a time period of more than 10 years. These study results have been derived from a separate, ongoing project that has monitored deformation on the Ataturk Dam and is now determining the water level of the reservoir. The project results show that although the dam body has become more stable and the water load behind the dam has increased, the rate of displacement of the dam has declined significantly. From these results, it can be seen that the reservoir water level can be increased evenly over time and that 542 m is the maximum water level of the dams reservoir.