Assessing velocity, energy, and duration parameters to explain damage discrepancies under similar PGA: Evidence from recent Turkish earthquakes

This study presents a comparative analysis of the April 23, 2025 Silivri (Istanbul) and February 6, 2023 Pazarcık earthquakes, which exhibited significant differences in structural damage outcomes despite having similar peak ground acceleration (PGA) values. The primary objective of the research is to question whether seismic demand can be more accurately explained not only through acceleration-based parameters but also through velocity- and energy-based ground motion indicators. Within the scope of the study, velocity and displacement time histories, Arias Intensity, spectral acceleration (Sa), spectral velocity (Sv), spectral displacement (Sd), significant duration, seismic input energy (Ei), and input energy equivalent velocity (Vi) parameters were calculated. Data recorded at stations from both earthquakes were comparatively evaluated in terms of peak ground velocity (PGV), energy content, and record duration. The analysis results revealed that velocity-based and energy-based parameters, such as PGV, Cumulative Absolute Velocity (CAV), and Vi were significantly higher in the Kahramanmaraş earthquake compared to the Silivri event. Similarly, significant duration values reached up to 50–70 s for the Kahramanmaraş earthquake, whereas they remained below 20 s in the Silivri earthquake. This indicates that a more intense and prolonged energy transfer occurred in Kahramanmaraş, resulting in greater dynamic demand on structures. Spectral analyses showed that records from the Kahramanmaraş earthquake exhibited high-magnitude Sa and Sv values within the 0.5–1.5 s period range, explaining the more severe impact on mid-rise reinforced concrete buildings. Moreover, a meaningful correlation was identified between station-based damage ratios and energy-based parameters, such as Vi and significant duration. The findings demonstrate that analyses based solely on PGA may be insufficient for evaluating earthquake effects, and that incorporating parameters, such as PGV, energy content, and duration can lead to more reliable structural damage predictions. In this context, it is recommended that energy-based ground motion parameters be integrated into regional seismic hazard assessments and performance-based design criteria.