How Do Earthquakes Cause Damage ?
Earthquakes cause direct damage when the seismic disturbance weakens and collapses buildings and other infrastructures not built to withstand the tremors. This often causes great loss of life. Other damage caused by earthquakes results from landslides, mudslides, avalanches, fires, soil liquefaction and tsunamis.
In the Tangshan earthquake of 1976, considered the most devastating earthquake of the twentieth century, up to 650,000 people died, mostly due to inadequate building construction. In the Kobe earthquake of 1995, over 100,000 buildings collapsed and about 80,000 more were damaged. Often roads, bridges and railroads buckle and crack because of the shifting ground.
Landslides, mudslides and avalanches result from the instability on slopes affected by earthquakes. Fires are caused by damaged electric and gas lines, and once they start fires are difficult to control due to overwhelmed emergency services. After buildings collapsed in the initial tremors of the Kobe earthquake, thousands of buildings burned to the ground. Soil liquefaction occurs during intense shaking when the soil loses its stability and turns into a quicksand-like fluid that can swallow buildings. Tsunamis are often caused by earthquakes beneath the ocean floor. Barely recognizable at sea, they can rapidly travel vast distances, increase dramatically in height as they approach and cause immense damage when they makr landfall.