There is a growing interest and relevance in the interaction between science and society reflected in the economic, social and public-policy aspects of hazards. This distinction is expressed by the word 'risk' (which incorporates both hazards, their consequences and their likelihood) which covers a wider scope than the word 'hazard'. The main difference between geophysical hazard and geophysical risk is that consideration of the risk involves some consideration of the people who are at risk.

One of the major social phenomena since the time of the industrial revolution has been the growth of cities in general, and megacities in particular. The recently invented word "megacity", calls attention to extraordinarily large metropolitan urban areas - those with 10 million or more inhabitants. The number of cities that can claim this distinction has climbed from 5 in 1975, to 14 in 1995 and is expected to reach 26 cities by 2015. The majority of this increase is expected to occur in less developed regions of the world and at a faster pace in these regions.

The International Union of Geodesy and Geophysics (IUGG) is dedicated to the scientific study of the Earth and the application of the knowledge gained by such studies to the needs of society, such as more rational use of mineral resources, reduction of the effects of natural hazards, and environmental protection. The Union's objectives are the promotion and coordination of physical, chemical, and mathematical studies of the Earth and its environment in space. These studies include the dynamics of the Earth as a whole and of its component parts, the Earth's internal structure, the hydrologic cycle including snow and ice, all aspects of the oceans, the atmosphere, the ionosphere, magnetosphere, and solar-terrestrial relations.

In August 2000, the IUGG Executive formed the "Commission on Geophysical Risk and Sustainability" (GeoRisk Commission).

The initial focus for the GeoRisk commission will be on the geophysical hazards to which cities are subject, the risks that these hazards pose to their inhabitants and their infrastructure. The purpose of the GeoRisk commission is the promotion of scientific studies applied to the reduction of risk from natural hazards in an increasingly urbanised world.