Current code requirements often allow buildings to be permanently damaged following a major earthquake as long as the occupants are protected, in other cases, the code requires that buildings remain usable following an earthquake (e.g. hospitals)
Structural elements are therefore often enlarged in order to meet these requirements. A category "A" or "B" building where moment resisting frames and concrete shear walls are used exclusively, is highly inefficient and wasteful. Given that steel and concrete represent major contributors to CO2 emissions, enlarging structural elements should be a last resort.
When buildings are damaged but remain intact the cost to repair is often so significant that the building must be torn down. This outcome is also extremely wasteful, both economically and environmentally.