A variational approach for energy-based analysis of near-fault pulse-like seismic records

Near-fault earthquakes often exhibit a pulse in the velocity time-history that mainly occurs in the strike-normal direction at locations towards which the earthquake rupture has propagated. The extraction of the dominant impulsive component embedded into such kind of seismic records and the proper consideration of the other signal modes are critical tasks for a reliable prediction of the behavior of structural systems subjected to earthquakes close to active faults. Within this framework, the present work is concerned with the application of the Variational Mode Decomposition technique for processing near-fault pulse-like seismic signals. Specifically, this numerical technique is herein applied to some fault-normal horizontal pulselike seismic velocity time-histories in order to evaluate its suitability in detecting the mode with the dominant pulse. Final results demonstrate that such variational approach is able to extract the impulsive component of the seismic records, and the corresponding estimates of the pulse period are in good agreement with the results obtained by means of existing methods. Input power and energy as well as acceleration, displacement, velocity and energy spectra have been calculated for the original seismic record and the modes extracted by means of the Variational Mode Decomposition technique.