Image caption Many major cities lie on fault lines

Earthquakes have a bigger impact on health than other natural disasters such as floods and hurricanes, US researchers say.

There are more than a million earthquakes, of varying severity, around the world each year.

As well as the immediate deaths, many people receive serious injuries which cannot be treated because of the quake damage to infrastructure.

The Lancet review says children are often at particularly high risk.

Many of the world's major cities are on fault lines, including Los Angeles, Tokyo, New York, Delhi and Shanghai, putting millions of people at risk from earthquakes.

In the past decade, earthquakes have caused more than 780,000 deaths - almost 60% of all disaster-related mortality. Other disasters, such as floods and hurricanes typically cause many deaths from drowning, but fewer injuries.

It is estimated that for every person killed in an earthquake, three others are injured.

Suicides

Depression can also be common after earthquakes - affecting up to 72% of the population.

Following the 1999 Turkey earthquake, 17% of the population had suicidal thoughts.

Children are often at higher risk of injury and death during earthquakes than adults. In Haiti in 2010, 53% of patients were younger than 20 years old and 25% were under five.

The team, led by Dr Susan Bartel of the Harvard Humanitarian Initiative in Boston, wrote in the Lancet: "Because earthquakes frequently affect populous urban areas with poor structural standards, they often result in high death rates and mass casualties with many traumatic injuries."