Underdamped elastic response spectra of microtremors using Newmark's β-method

In the absence of seismic records, this study focuses on using microtremors as surrogates to analyze ground signals during earthquakes. Earthquake engineering uses response spectra to evaluate the structural reaction to vibrations, condensing the complex dynamics required for design. The central objective is to generate response spectra in underdamped systems using Newmark's β method, considering displacement, velocity and acceleration with operations research methodology. The sample consists of 171 points of the Riobamba seismic zonation study. Using environmental microtrepidation results, accelerogram matrices were obtained for each component. Maximum values of displacement, velocity and acceleration were extracted for a natural period of 3 seconds with a damping of 5% and plotted to obtain response spectra. This methodological approach provides a robust analysis of the underdamped response of the system, offering crucial insights for seismic design and engineering.