What are the two main types of geologic hazards?

The distinction between slow phenomena and sudden phenomena in the context of geologic hazards is significant because it highlights the varying scopes and impacts of these events. Slow phenomena refer to gradual changes in the earth's surface, such as erosion or subsidence, which can lead to long-term impacts like land loss or infrastructure damage over time. Sudden phenomena, on the other hand, are rapid events like earthquakes, landslides, or volcanic eruptions that can occur with little warning and cause immediate and often catastrophic effects.

This framework of categorizing geologic hazards into these two main types helps in understanding the nature of risks involved and informs preparedness and response strategies. It emphasizes the need for different approaches in management and disaster planning, as the response required for a sudden event differs significantly from one that develops slowly over time. The other types listed, while being specific hazards or consequences of geologic activity, do not encapsulate the broader classification system that helps in understanding their timing and impact.