Earthquakes claimed more than 780,000 lives in the past decade, accounting for nearly 60 per cent of all disaster-related deaths, according to a study published in The Lancet.
“In addition to these deaths, earthquakes have directly affected another two billion people in this period,” it added.
The deadliest quake was the January 12, 2010 7.0-magnitude event in Haiti which killed 316,000 people.
This was followed by the December 26, 2004 Indian Ocean tsunami, generated by a 9.1-magnitude temblor, in which 227,000 people died.
Third-ranked was the May 12, 2008 7.9-magnitude quake in southwestern China’s Sichuan province, which inflicted a death toll of 87,500.
The review study seeks to give emergency responders and policymakers a snapshot of the scale of earthquakes as a health priority, and to warn doctors about the kind of injuries they are likely to confront.
“Massive earthquakes can result in casualty rates ranging from one to eight per cent of the at-risk population,” it said.
“The reported ratios of death-to-injury vary, but across many studies seems to be about 1-to-3.”
The death toll unfurls in waves, starting with immediate fatalities from falling buildings, which is followed several hours later as people die from catastrophic injuries to internal organs, says the investigation.
A third wave occurs in the days to weeks afterwards among people with sepsis and multiple organ failure.
Among survivors, the main injuries are crush-related damage to the kidneys, liver and spleen, followed by spinal damage, bone fractures and lacerations.
Children are the most vulnerable group, accounting for between 25 and 53 per cent of earthquake patients.
Beyond immediate search-and-rescue operations, care workers must deal with problems of infectious disease in crowded shelters.
Contrary to popular perception, cadavers are not a risk unless there is an outbreak of cholera.
In the longer term, earthquakes also exert a heavy impact on mental health, with high prevalence of depression.
The study was conducted by Susan Bartels of the Beth Israel Deaconess Medical Centre in Boston, Massachusetts, and Michael van Rooyen of the Brigham and Women’s Hospital, also in Boston. The pair warned that the threat from earthquakes is set to intensify as the world’s population grows and cities expand in vulnerable zones.
Cities in seismic regions include Tokyo (32 million inhabitants), Mexico City (20 million), Los Angeles (15 million) and Istanbul (nine million), the authors noted.