Certain actions increase the chance of surviving a devastating landslide, and simple behavioral changes could save more lives than expensive engineering solutions, according to a new study in AGU’s journal GeoHealth.
In the study, Pollock and Wartman compiled and analyzed a data set of landslide events from around the world that affected occupied buildings, with most of the data coming from the United States. The results showed behavioral factors (such as having knowledge of local landslide hazards and moving to a higher floor during a landslide) had the strongest association with survival, regardless of the size or the intensity of landslide events. The authors also found that stories from landslide survivors provide general strategies for reducing the risk of death.
“There are, in fact, some really simple, cost-effective measures…that can dramatically improve the likelihood that one will survive a landslide,” said Joseph Wartman, a geotechnical engineer at the University of Washington in Seattle and senior author of the new study.
Worldwide, landslides cause over 4,000 deaths per year, on average. In the United States, they are estimated to kill 25 to 50 people each year. In March 2014, the Oso landslide in Washington became the deadliest landslide event in U.S. history, resulting in 43 deaths and destroying 49 homes and structures. Yet scientists haven’t analyzed why some people survive landslides and others don’t.
“We really found there was very little information out there,” said William Pollock, a geotechnical engineer at the University of Washington and lead author of the new study. He and Wartman dug through the scientific literature, newspaper articles, medical examiner reports, and other documents to produce a detailed catalog of fatalities caused by landslides hitting occupied buildings. The data set includes information from 38 events that occurred from 1881 to 2019 in Asia, North America, and Oceania. Their analysis showed factors like the distance of the building to the landslide slope, one’s gender, and one’s age were less associated with survival than behavioral factors like moving away from the direction of the threat, rather than getting closer out of curiosity.
In particular, the researchers found some behaviors, despite being performed by only a small number of people in a community, often save lives. These actions are much simpler and may be more effective than expensive engineering solutions, according to the study authors. Specifically, individuals can do the following to increase their chance of survival during a landslide.
Before an Event
- Be informed about potential hazards, and talk to people who have experienced them.
- Move areas of high occupancy, such as bedrooms, upstairs or to the downhill side of a home.
During an Event
- Escape vertically—this includes moving upstairs and even on top of counters to avoid being swept away.
- Identify and relocate to the interior, unfurnished areas.
- Open downhill doors and windows to let debris escape.
After an Event
- If caught in landslide debris, continue to make noise and motion to alert rescuers.
The authors have produced the most robust analysis of interactions between landslides and humans yet, said Dave Petley, vice president for innovation at the University of Sheffield in the United Kingdom and author of the Landslide Blog. Although the new study provides practical advice for people living in landslide-prone areas, the analysis was limited to people in buildings, added Petley, who was not involved in the research. Further analyses of other scenarios, such as people who encounter landslide events on roads or out in the open, may provide additional findings.
The scientific results in the study offer the possibility of markedly decreasing the number of lives lost to landslides in the United States, Wartman said, especially if included in community awareness programs.
“This is a message of hope,” Wartman said. (GeoHealth, https://doi.org/10.1029/2020GH000287, 2020)
—Jack J. Lee (@jackjlee), Science Writer