The application Dual Echo, allows the estimation of the phenomenon of double resonance building / ground responsible for the most damage in case of an earthquake.
For the calculation of the resonance frequency of the building, consolidated formulations in technical literature and reported on European legislation are applied.
The frequency with which the resonance occurs in the soil is described by the law:


Valid for cover systems of bedrock-like, where the only visible way is the basic one.
The graphical representation of the resonance frequencies of the structure/ground is provided with information if a double resonance is present.