Ganos fayı güncel deprem etkinliğinin değerlendirilmesi: MONGAN sismik ağ yapısı ve veri kalitesi

Abstract

The current seismicity and stress distribution of the Ganos Fault, which was ruptured by two major earthquakes in 1912, show significant differences along the fault. While the land and Saros part of the fault exhibit an asismic (non-earthquake producing) behavior, the part in the Marmara Sea has a very intense earthquake activity. It is clear that the differences in the geometric and physical properties of the fault and the changing stress conditions along the fault can create such behavioral differences. MONGAN seismic observation array consists of a total of 40 stations on the land of the Ganos Fault and has collected data for about 3 years. It is expected that the obtained data will contribute both to the physical properties of the fault and to the seismicity that occurs. In the first part of the study, which consists of two contiguous articles, which are the continuation of each other, the distribution of the seismic array and the data quality are emphasized. The second part consists mostly of primary data analysis and seismological evaluations (Yalçınkaya et al. 2022). In the study where two different types of sensors and recorders were used, it was determined that 4,5 Hz Geophone sensor and CUBE recorder provided much higher data collection efficiency than 1 Hz Mark sensor and EDL recorder. It has been observed that both sensors are sensitive to ground vibrations up to 0,3 Hz frequencies, and instrument internal noises begin to dominate at lower frequencies. It has been calculated that the noise levels observed at the stations can allow to detect earthquakes up to negative magnitudes. It is seen that the bimaterial structure of the Ganos Fault will have significant effects both in terms of near surface effects and on records such as transformed wave phases and fault zone waves. The stations located in the southern block of the fault, which consists of younger and looser units, exhibit much longer recording times and much larger wave amplitudes than the stations located on the older and stiffer northern block. The ground resonance frequencies obtained from the H/V analyzes at the stations clearly reveal the two-block structure.