artquakes are among the deadliest natural disasters, causing the largest number of casualties, the highest death tolls, and the greatest destruction. In1556 in china, the deadliest earthquake in history killed 840,000 people, But many other earthquake have caused the dead of more than 100,000 people and isn’t unusual, even in modern times, for an earthquake death toll to reach 20,000 to 20,000 people with hundreds of thousands left homeless.
There are four factors that affect the casualty rate and economic impact of earthquake: magnitude, location, quality of construction of building, and timing. Magnitude
The magnitude, or strength, of an earthquake is measured on the Richer scale, ragging from 1to 10, with 10 being the greatest. Earthquake over 6 on the Richter scale are often deadly, and those over 8 are generally catastrophic, causing terrible damage. Location
However, a sever earthquake that is located far from population centers does not cause the same damage as a less sever one that occurs in the middle of a city. As an example, in 1960, the strongest earthquake recorded, 9.5 magnitudes on the Richter scale, struck in the Pacific Ocean near the Chilean coastline, killing over 2,000 people and injured another 3,000. If this quake had struck a city, it would have been killed. Similarly, in Alaska, in 1964, a magnitude 9.2 quake hit an area with few people, and the death toll was 117. Quality of Construction
Furthermore, modern building construction technique can lessen the death toll and economic impact of moderate earthquake that would otherwise cause severe destruction of older-style buildings. In 2003, a terrible earthquake in the historic city of Bam in Iran caused the destruction of over 90% of the buildings, mostly due to old construction. Timing
Finally, the time of occurrence of an earthquake can affect the number of deaths and casualties. Earthquakes that occur in the night, when people are indoors usually cause a greater death toll...
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