Earthquake Hazards Overview

Earthquake hazards include any physical phenomenon associated with an earthquake that may produce adverse effects on human activities. While they are often used as synonyms, it is useful to distinguish between "hazards" and "risk". Hazards are the natural phenomena that might impact a region, regardless of whether there is anyone around to experience them or not. Risk refers to what we stand to lose when the hazard occurs; it is what we have built that's threatened. Risk can usually be measured in dollars or fatalities. Hazard is generally measured in more physical units: energy, shaking strength, depth of water inundation, etc.

Primary earthquake hazards are:

Secondary earthquake hazards are those that are caused by the primary hazards, and may often be more catastrophic: