When it comes to reckoning how many deaths can be attributed to landslides, a new study shows previous estimates were off by, well, a landslide. Actual annual landslide deaths could be more than ten times what was once thought, according to analysis of new data collected over seven years, published in Geology this month.

“We need to recognise the extent of the problem and take steps to manage what is a major environmental risk to people across the world,” said Durham University geographer David Petley in a statement. “Our database will enable us to do this by identifying areas most at risk and could help to save thousands of lives.”

The database showed about 32,300 people died in landslides between 2004 and 2010. Previous estimates for that timeframe ranged from 3,000 to 7,000 fatalities, according to a Durham press release. The discrepancy likely derives from how—and if—the deaths are categorized, Petley said.

"Other data sets tend to collect data on the basis of trigger—hurricane or typhoon,” he told BBC News. “Most of the other data sets also have a higher threshold—they only record events that kill 10 people or more, for example, but there are lots of landslides that kill relatively small numbers of people.”

Even this new accounting doesn’t square the books. Because his database doesn’t include seismically induced landslides, Petley believes the numbers are even higher. In those events, it’s often too difficult to tell whether the cause of death was the earthquake, the landslide, or some other factor.

More information on the data analysis (including maps, an unpublished list of landslide deaths by country, and a helpful offer to e-mail readers a copy of the recent paper) is available on Petley’s Landslide Blog.

“Landslides are a global hazard requiring a major change in perception and policy,” he said in the statement. “There are things that we can do to manage and mitigate landslide risks such as controlling land use, proactive forest management, and guiding development away from vulnerable areas.”