Simple actions can help people survive landslides

October 22, 2020

The March 2014 landslide in Oso, Washington, about 55 miles northeast of Seattle, became the deadliest landslide event in United States history. Forty-three people died and 49 homes and structures were destroyed.

A University of Washington engineer who analyzed the event's aftermath began to investigate the circumstances that can make landslides so deadly. The resulting study shows that certain human actions increase the chance of surviving a devastating event, and suggests simple behavioral changes could save more lives than expensive engineering solutions.

The open-access study, published in the October issue of GeoHealth, suggests key actions that range from opening doors and windows to continuing to move and make noise if you do get buried.

"There are in fact some really simple, cost-effective measures that can be taken that can dramatically improve the likelihood that one will survive a landslide," said senior author Joseph Wartman, a UW professor of civil and environmental engineering.

Worldwide, landslides cause on average more than 4,000 deaths a year recently, with about 25 to 50 of those deaths occurring each year in the U.S. These events may become more frequent as wildfires fueled by warmer temperatures can leave slopes bare and more vulnerable to slides.

Wartman and a UW graduate student compiled and analyzed records of 38 landslides that affected occupied buildings. Most of the data came from the U.S., but it included landslides from around the world for which there were detailed records.

The authors recorded the geologic details of each landslide, as well as the reports from survivors of the events. They used newspaper articles, scientific papers, medical examiner reports and other documents to produce a detailed catalog of fatalities caused by landslides hitting occupied buildings. The events, spanning from 1881 to 2019, included the Oso mudslide and the 2018 mudslide in Southern California, as well as events in Bangladesh, Philippines, China, Malaysia, Australia and New Zealand.

Their analysis showed behavioral factors, such as a having an awareness of local landslide hazards and moving to a higher floor of a building during an event, had the strongest association with survival.

"Simply by being on an upper floor, an individual can increase their odds of survival by up to a factor of twelve. This is a powerful finding that we need to consider when we design the layout and vertical access routes in homes," said first author William Pollock, who did the work for his UW doctorate in civil and environmental engineering and is now a lecturer in the department.

The analysis showed many things they predicted would be important, including the size or the intensity of landslide events, made little difference to the death toll for landslides below about 20 feet depth. Similarly, the distance between a building and the landslide slope, or an inhabitant's age and gender, didn't make a big difference to their survival.

But the researchers found some behaviors, despite being performed by only a small number of people, often save lives. According to their results, those actions are:

Before an event During an event After an event The results suggest practical ways to lower the number of lives lost to landslides in the United States, Wartman said. He hopes the information can be incorporated in education and community awareness programs.

"This is a message of hope," Wartman said. "What this work suggests is that a modest investment put toward social science, policy and education could have a very marked effect in protecting people from landslides."

Residents who want to know if they are vulnerable to landslides can contact a local agency, such as the Washington State Department of Natural Resources, to learn more about local risks. Federal legislation is pending to make this information more easily accessible across the United States, Wartman said.
-end-
The study was funded by the National Science Foundation.

For more information, contact Wartman at wartman@uw.edu or Pollock at wpollock@uw.edu.

University of Washington

Related Landslides Articles from Brightsurf:

Simple actions can help people survive landslides
Simple actions can dramatically improve a person's chances of surviving a landslide, according to records from 38 landslides in the US and around the world.

Landslides have long-term effects on tundra vegetation
Landslides have long-term effects on tundra vegetation, a new study shows.

Most landslides in western Oregon triggered by heavy rainfall, not big earthquakes
Deep-seated landslides in the central Oregon Coast Range are triggered mostly by rainfall, not by large offshore earthquakes.

FSU researcher detects unknown submarine landslides in Gulf of Mexico
A Florida State University researcher has used new detection methods to identify 85 previously unknown submarine landslides that occurred in the Gulf of Mexico between 2008 and 2015, leading to questions about the stability of oil rigs and other structures, such as pipelines built in the region.

Climate change could trigger more landslides in High Mountain Asia
More frequent and intense rainfall events due to climate change could cause more landslides in the High Mountain Asia region of China, Tibet and Nepal, according to the first quantitative study of the link between precipitation and landslides in the region.

Martian landslides not conclusive evidence of ice
Giant ridges on the surface of landslides on Mars could have formed without ice, challenging their use by some as unequivocal evidence of past ice on the red planet, finds a new UCL-led study using state-of-the-art satellite data.

Ground failure study shows deep landslides not reactivated by 2018 Anchorage Quake
Major landslides triggered by the 1964 magnitude 9.2 Great Alaska earthquake responded to, but were not reactivated by, the magnitude 7.1 Anchorage earthquake that took place 30 November 2018, researchers concluded in a new study published in Seismological Research Letters.

Rice irrigation worsened landslides in deadliest earthquake of 2018 finds NTU study
Irrigation significantly exacerbated the earthquake-triggered landslides in Palu, on the Indonesian island of Sulawesi, in 2018, according to an international study led by Nanyang Technological University, Singapore (NTU Singapore) scientists.

Precursors of a catastrophic collapse
The flanks of many island volcanoes slide very slowly towards the sea.

Quick reconnaissance after 2018 Anchorage quake reveals signs of ground failure
A day after the Nov. 30, 2018, magnitude 7 earthquake in Anchorage, Alaska, US Geological Survey scientists Robert Witter and Adrian Bender had taken to the skies.

Read More: Landslides News and Landslides Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.