Spectral entropy of acceleration data for damage detection in masonry buildings affected by seismic sequences

One of the main drawbacks of using entropy-based indicators for damage detection is known to be their sensitivity to the energy introduced into the system. Indeed, energy supply can lead to a more deterministic behavior of the structure and thus to a reduction of the entropy. As a solution to these issues, in this paper an indicator based on two measures of spectral entropy is proposed to assess the occurrence of damage in masonry buildings, even in the presence of an external unmeasured input (e.g. minor seismic event). The proposed indicator was first validated by using a benchmark numerical model. Subsequently, the methodology was applied to dynamic response data from three monitored masonry buildings that were affected by the 2016–17 seismic sequence in Central Italy.