New model can predict landslides caused by earthquakes

Scientists have developed a model that can estimate the likelihood of landslides caused by earthquakes anywhere in the world.

The estimates can be available within minutes, providing potentially life-saving information to people who are affected by earthquakes and the agencies and organisations charged with responding to them.

The 2008 Wenchuan earthquake in Sichuan, China, killed tens of thousands of people and left millions homeless, said researchers at Indiana University in the US.

About 20,000 deaths - nearly 30 per cent of the total - resulted not from the ground shaking itself but from the landslides that it triggered, they said.

"Earthquakes can be devastating, horrific and stressful events," said Anna Nowicki Jessee, a postdoctoral research fellow at Indiana University.

"The ultimate goal of this work is that fast, regional estimates of landslide occurrence would provide a way for those who are affected to receive the aid they need more quickly and efficiently," said Jessee, who developed the model described in the Journal of Geophysical Research: Earth Surface.

The model, based on data from past earthquakes and landslides, will be incorporated into the US Geological Survey's Ground Failure tool, which will be part of the USGS earthquake reporting system.

The model describes a mathematical relationship between where landslides happen and five key variables: how much the ground shook during an earthquake; the steepness of the ground; the type of rock affected; an estimate of how wet the ground is; and what type of land cover is present.

The researchers tested multiple versions based on past earthquake-triggered landslides and selected the model with predictions that best matched where landslides occurred.

By entering data for ground shaking for a specific earthquake - available anywhere around the globe from the USGS ShakeMap tool - scientists will be able to use the model to produce a map showing the probability of landslides in areas near the quake.

Available within minutes, the results could provide this information quickly to agencies that assist affected populations.

Landslides are the third-largest contributor to earthquake deaths, after building collapse and tsunamis. From 2004 to 2010, earthquake-induced landslides caused an estimated 47,000 deaths, researchers said