Hazardous siting of dwellings

Cities and settlements are increasingly built on marginal areas, on low-lying coastal areas, on river deltas, and on steep slopes, because of pressure on land use. Such locations are hazardous, notably where there is risk of earthquakes, landslides, avalanches, or flooding. Even in the absence of flooding, coastal flood-plains and river deltas, made of silt or sand, can be shaken by earthquakes in such a way that the soil effectively liquifies. The liquid sand solidifies once the shaking has ceased, by which time buildings may have partially sunk or tilted.