Natural hazards are naturally-occurring physical phenomena caused by either rapid or slow onset events having atmospheric, geologic and hydrologic origins at the global, regional, national or local scale. They include earthquakes, volcanic eruptions, landslides, tsunamis, floods, tropical cyclones, and drought and desertification.
Natural disasters are the consequences or effects of natural hazards, but natural phenomena do not automatically spell disaster.
As the UN's agency for science, UNESCO has been intimately involved in disaster reduction for the past 45 years, with studies on earthquakes and oceanography dating back to the 1960s. It has since expanded into many areas, as it pursues multidisciplinary actions to study natural hazards and mitigate their effect.