NDSHA - Computational Aspects of the Neo-Deterministic Seismic Hazard Assessment

Reliable assessments of ground shaking scenarios with the aid of computers before the occurrence of an earthquake can be of extreme value in planning the design of new structures, or in retrofitting of existing ones in the areas of interest. Obtaining realistic estimates of the ground motion expected in case of an earthquake is a task that seismologists tackle using dedicated and powerful computational software. The time series generated, and the corre- sponding response spectra, can be used by civil engineers in designing seismo- resistant structures capable of surviving future earthquakes with limited dam- age. The complexity of the earthquake phenomenon usually translates into powerful but unfriendly software that can intimidate those who might be inter- ested but not familiar with the matter. A web application has been developed that isolates the user from the intricacies of the underlying computational en- gine, and a friendly graphical user interface allows for the modelling of ground shaking scenarios based on the knowledge of the physical properties of the earthquake source and of the medium through which travel the seismic waves. Some predetermined source and soil models can be selected, or new, ad-hoc models can be generated or uploaded by the user. The underlying computation- al engine allows the generation of the time series (displacement, velocity, ac- celeration) in a matter of seconds for the simplest configurations. With an ac- ceptable computational time, more detailed modelling of the source rupturing process and of the layering underneath the sites of interest can be taken into ac- count, depending on the characteristics of the model.