Short course on Seismic Wave Propagation

Pavia, 14-18 March 2005

Waves propagating in the Earth crust are the main cause of damage during earthquakes, as carriers of kinetic energy that is transferred through strong ground shaking both to the built environment (structures and infrastructural systems, or lifelines), and to the geological environment, e.g. by inducing ground ruptures and soil liquefaction.

In Earthquake Engineering courses "even at an advanced level" and textbooks, the topic of wave propagation is typically confined within few pages, mostly limited to the simple one-dimensional case. However, understanding the catastrophic damage occurred in many earthquakes, such as Kobe 1995, requires a comprehensive picture that includes the seismic source and the wave propagation in a complex 3D geological configuration, in addition to the characteristics of the building stock.

This short course will first provide the basics of linear elastic wave propagation in one dimension (1D), including the boundary conditions appropriate for the most elementary earthquake source models and the local site amplification problem. Assessing of seismically induced stresses in underground pipes, with examples, will be illustrated as an application of the 1D theory. The latter will be completed by introducing earth materials with viscoelastic dissipation, allowing to describe real nonlinear geomaterials by an equivalent linear approximation widely adopted in engineering applications. The effectiveness and limits of the 1D soil amplification approach will be extensively demonstrated with real case histories. Current numerical tools for seismic site response analysis will be illustrated and participants will be trained in their use.

The final part will deal with the formulation of the 3D elastodynamic equations, and general aspects of their solutions. Plane waves, with their reflection, refraction and polarisation properties will be illustrated, and simple but useful cases of "topographic amplification" will be treated by way of example, providing also a background for the corresponding design provisions of Eurocode 8. Surface waves will also be (concisely treated), owing to their extended use in experimental methods for measuring the seismic wave propagation velocity.

The course is fully organised by Prof. Ezio Faccioli and Dr. Roberto Paolucci, from the Politecnico di Milano, who will be responsible for all lecturing activities. Further details can be obtained by following the links below: