Effects of Earthquake

An earthquake is a natural hazard, and its effects can be grouped into two broad categories: those that directly shape the land and those that immediately threaten human life and property. The book lists twelve immediate hazardous effects, and the first six of these have a direct bearing on landforms. The remaining six are primarily concerns for people living in the affected region.

The twelve effects are:

• Ground shaking
• Differential ground settlement
• Land and mud slides
• Soil liquefaction
• Ground lurching
• Avalanches
• Ground displacement
• Floods from dam and levee failures
• Fires
• Structural collapse
• Falling objects
• Tsunami

The first six — ground shaking, differential ground settlement, land and mud slides, soil liquefaction, ground lurching, and avalanches — are the ones that leave a mark on the landscape itself. The others, such as fires, structural collapse, and falling objects, are the effects that cause immediate concern for the safety of life and property in the region.

A tsunami occurs only under specific conditions: the epicentre of the tremor must lie below oceanic waters, and the magnitude of the quake must be sufficiently high. It is important to understand that a tsunami is not an earthquake in itself — it is a wave generated by the tremors. Even though the actual shaking lasts only a few seconds, the destruction can be devastating, provided the magnitude of the quake exceeds 5 on the Richter scale. …