Vocabulary

Geohazard - a dangerous geological phenomenon that can cause harm to people or cities
Volcano - anywhere on earth where magma escapes to the surface
Earthquake - a large and quick shift in earth's crust that releases dangerous seismic waves
Landslide - a large movement of land downhill
Tsunami - a large ocean wave usually caused by an underwater earthquake
Avalanche - a large movement of ice and snow downhill

​It's important for engineers and city planners to take into consideration possible geohazards before building. Some areas are impossible to maintain, while others need specialized structures to withstand earthquakes, high winds, water, etc.