What are the effects of an earthquake?
According to the Office of Disaster Preparedness and Emergency Management (ODPEM), these are some of the possible physical results of an earthquake:
- Tsunamis – Earthquakes that occur undersea or near the coastline strong enough to shake the ocean floor and disturb the mass of water over it can generate waves that travel at speeds up to 800km (500 miles) per hour.
- Land shifts and scarps – Sections of ground may be elevated or subside. Sometimes one side of a fault will rise or sink, creating a cliff, called a scarp. Scarps may be lifted again and again in successive earthquakes, with the movement ranging from a few centimeters to several metres or more.
- Landslides – Unstable hillsides may slump or slide during or after the shaking. Rocks may break loose and slide downhill, sometimes creating rock avalanches. The potential for landsliding is highest in soft sediments on steep slopes; where seasonal rainfall is high, vegetation is shallow, rotted or sparse,
- Water changes – The underground water system may also be disturbed by an earthquake, causing fluctuations in water pressure and stream volume, and the appearance or disappearance of springs. Well water levels or temperature can change, and the water can become cloudy and muddy. Underground oil and gas deposits may be similarly disturbed.
- Soil liquefaction – Loose soils with a high water table (water in the soil close to the surface) may experience the phenomenon of liquefaction. As the earthquake’s vibrations pass through the loose soil, it becomes like quicksand. Heavy objects such as buildings and other structures situated over such areas may sink or tilt into the liquefied soil.