Quantification of Ground Motion Intensity Using 3-Dimensional Input Energy Spectrum

Abstract

Ground motion recordings from the field stations provide a basis in understanding the seismicity in the monitored region. The recordings are studied in either time or frequency domain to determine the intensity of the motion and severity on the structural systems. Several intensity measures have been introduced in the current literature to assess the ground motion recordings. These measures are based on two facts, namely, ground motion time history and response spectra of the records. Despite the fact that both approaches are adequately representing the seismic intensity, a better way is required if the progress of the structural response throughout the motion is considered. Such necessity becomes more apparent if a direction-independent quantification is considered. Energy concept in the definition of a dynamic motion's intensity enables the researchers to have an overview of not only ground motion but also the structural response. This study reveals the superiority of energy time history and consequently the spectrum approach in the quantification of intensity measure of a given set of ground motions. The freedom of the ground motions were taken as not only horizontal but also vertical to have a better understanding of the effect of excitation and response. Since the energy terms are scalar, the privilege of covering the whole motion space is inherently found in the summed values. By means of that, intensity measure of the ground motion and structures response is undoubtedly expressed implicitly with all given spatial features. An extensive set of ground motions recorded during the 2023 Pazarcik (M7.7) earthquake was used in the comparison of the recommended energy approach to the available intensity measures and results are found to be future promising in the development of a novel energy-based measure into the literature.