Chapter 2: Basic concepts of engineering seismology and seismic hazard analysis

The goal of earthquake-resistant design is to minimise seismic risk, defined as the possibility of casualties and economic and cultural loss due to seismic events. This is achieved by ensuring that a structure can withstand the expected level of ground shaking while maintaining a desired level of performance, or, in other words, that the seismic capacity of the structure is equal to or larger than the expected seismic demand. While the seismic capacity depends on the level of exposure and vulnerability of the structure, which can be controlled and predicted by designers and planners, the seismic demand, or prediction of the expected level of ground shaking, requires characterisation of the ground shaking hazard due to future earthquakes for the site of interest. This chapter focuses on the definition of the expected level of the ground at the site of interest.