It happens at contact surfaces of a structure either with the ground, see The Geotechnical Earthquake Engineering Portal, or with adjacent structures, see Seismic Pounding between Adjacent Building Structures, or with gravity waves from tsunami, see Tsunami wave propagation.
Seismic load depends, primarily, on:
- Anticipated earthquake’s parameters at the site
- Geotechnical parameters of the site
- Structure’s parameters
- Characteristics of the anticipated gravity waves from tsunami (if applicable).
Sometimes, seismic load exceeds ability of a structure to resist it without being broken, partially or completely. Due to their mutual interaction, seismic loading and seismic performance of a structure are intimately related.