Is there a link between the size of an earth-quake and death toll?

Answer 1

Yes. The bigger the earthquake, the greater the number of deaths and injuries.

However, the place where the earthquake occurs, the time of day, the proximity of the nearest city, and the building standards are more important factors. In California or in Japan, where the building standards are fairly stringent, even a big earthquake won't kill a great number of people. However, recent earthquakes in China and in Iran have caused much larger casualty numbers. Why the difference? In Iran, the quake was close to the city, the city was quite ancient, and the buildings were made of un-reinforced brick and stone.

The biggest factor is, does the quake cause buildings to collapse? Very few people are killed by the earth shaking; people are killed and injured because the buildings fall down and crush people. In Japan many years ago, an earthquake caused a large building to TIP OVER and fall down; but because the building didn't collapse, the number of deaths was fairly small.

The biggest earthquake ever to hit the U.S. (that we know of) occurred in New Madrid, Missouri in 1812. Because none of the cities in the Midwest have building standards as strict as California's, another similar earthquake is likely to kill many more people than would be killed by a similar quake in Tokyo or in Los Angeles.

Answer 2

Yes, there is a general trend that larger earthquakes tend to cause more casualties. The severity of the earthquake, building codes, population density, and preparedness efforts in the region all play a role in determining the death toll.