When earthquakes occur, a variety of secondary and related hazards can happen simultaneously. The ground shaking from earthquakes can cause landslides, rockfall, debris flow, subsidence, soil liquefaction, or even snow avalanches. These ground failure-related hazards triggered by the ground shaking from earthquakes can contribute to additional loss of life and property losses. For example, when soil liquifies it loses its bearing capacity and is unable to support buildings. The buildings tilt or collapse, causing additional losses.

Earthquake ground shaking and related ground failure hazards can contribute to damage or failure of dams, bridges, utilities, and other structures. The earthquake damage to these facilities can cause even further loss of life and damage. (Refer to photos of the Northridge earthquake above.) For instance, flooding can occur after a dam failure and fire can result from damage to a natural gas pipeline. Hazardous toxic substances can be released after earthquakes causing damage to buildings or other facilities.

Landslides & Soil Liquefaction	Structure Failures	Infrastructure Damage
Interrupted Utilities	Toxic Releases	Dam Failures

Definitions and Introduction | The Modified Mercalli Intensity Scale | The Richter Magnitude Scale | Colorado's Seismic Risk | Secondary Hazard Events | Survival Tips