Post-Earthquake Site Characterization of Southeastern Türkiye: An Evaluation Using H/V Analysis Method

The horizontal to vertical spectral ratio (H/V) method is a widely used technique for assessing subsurface characteristics. It analyzes the ratio between horizontal and vertical seismic components of ambient vibrations (microtremors), providing valuable insights into the dynamic properties of the soil. This method is crucial in understanding soil behavior, including its fundamental frequency, site response, and dynamic soil conditions. Specifically, the H/V spectral ratio is useful in evaluating dynamic soil properties such as liquefaction, settlement, and variations in soil stiffness. These phenomena are particularly prominent in regions with high water tables, where soil may undergo liquefaction during seismic events, causing significant structural damage. Analyzing shifts in the H/V ratio can provide a better understanding of these soil behaviors and help predict the potential impacts of seismic events. The H/V technique is also a valuable tool in microzonation studies, which assess seismic hazards based on soil conditions, playing a crucial role in urban planning and construction.

On February 6, 2023, the Kahramanmaras region in Türkiye experienced a devastating earthquake with a magnitude of 7.7. This earthquake, one of the most destructive in Türkiye's history, caused significant loss of life and extensive damage to buildings, especially in Kahramanmaras and surrounding areas. The event was followed by a strong aftershock on the same day, further increasing seismic activity in the region. The Kahramanmaras earthquake highlighted the importance of understanding how strong seismic forces impact soil properties, making this analysis highly relevant for seismic risk assessments. Shifts in soil behavior due to such earthquakes must be closely studied to improve future risk management and construction practices.

This study analyses continuous seismic data collected from monitoring stations in Kahramanmaras and surrounding areas. The data will be used to observe changes in the H/V spectral ratios before and after the earthquake. These measurements will offer valuable insights into shifts in soil fundamental frequencies and structural changes following the earthquake. The hypothesis of this study is that changes in soil stiffness and structure will be reflected in these spectral shifts, which are essential for seismic hazard assessment, especially in urban areas. Understanding these changes is crucial not only for earthquake preparedness but also for improving construction practices in earthquake-prone regions. The findings of this study will help enhance safety measures and disaster response strategies by providing insights into the dynamic behavior of soil during seismic events. Additionally, the data will contribute to more informed decisions in urban development, helping mitigate potential damage caused by future earthquakes.

In conclusion, analyzing H/V spectral ratios following the Kahramanmaras earthquake is an essential step in assessing the impact of seismic forces on soil properties. The results from this study will significantly contribute to earthquake risk management and the development of safe urban planning strategies in seismic zones.