In April, as email alerts ricocheted with the news that a large earthquake had shaken Nepal near its capital, Kathmandu, experts somberly expected a toll comparable to the roughly 85,000 who died in 2005 when a smaller earthquake struck a more sparsely populated area in the Kashmir region.

Over the following days, the number of deaths in Nepal from the magnitude 7.8 earthquake rose to more than 9,000.

That figure “is actually a small number given the density of the population in the Kathmandu area and the vulnerability of the buildings,” said Jean-Philippe Avouac, a professor of geology at the California Institute of Technology and the University of Cambridge in England, and an author of two scientific papers published Thursday about the Nepal earthquake. “I think we understand why that is the case.”

The relatively low death toll is owed neither to blind luck nor the sturdiness of Nepalese construction.