Landslides are among the most pervasive hazards worldwide, causing thousands of deaths and billions of dollars in damage every year. But the exact number of landslides worldwide is unknown, as most publicly available inventories have gaps or uncertainties in where and when these mass movements of soil and rock take place.
In a study available online on July 3, 2019 in PLOS ONE, NASA scientists described a new source for increasing our knowledge of landslides around the world: citizen scientists. The Landslide Reporter project is the first and only landslide citizen science project that is global in scope. The idea is that if scientists can develop a better inventory of landslide occurrences, scientists can improve prediction models.
“We do not know the true distribution of where and when landslides happen,” said Dalia Kirschbaum, a landslide expert at NASA’s Goddard Space Flight Center. “By engaging citizen scientists in the process of finding and documenting these events, we hope to move the community closer to a global awareness of landslide occurrence and impacts.”
Kirschbaum leads the Cooperative Open Online Landslide Repository (COOLR), a publicly available inventory for the reporting and sharing of landslide data. The repository includes NASA's Global Landslide Catalog, which collects rainfall-triggered landslides reported in online news reports.
But the catalog is based mainly on information gathered from news reports, primarily written in English. Since journalists tend to cover only large and deadly landslides in densely populated areas, many events never make it into the database. To fill in the gaps, Kirschbaum and her team created the Landslide Reporter web application, where anyone can log in and report the time, location, date, size, cause, and photos of a landslide.
The map above shows citizen science reports compared to items being entered into NASA’s Global Landslide Catalog. The red points show European landslides reported by citizen scientists since March 2018, while yellow points represent reports added to the news-driven Global Landslide Catalog since 2007. Citizen scientist data is more prevalent over hilly regions of Germany and the Alps, where landslide susceptibility is high but reports from the NASA Global Landslide Catalog are sparse.
According to the study, 49 citizen scientists contributed 162 landslide events in the first 13 months of the project. The data came from sources in 11 languages and from in-person observations.
“It is clear from the 162 data points that citizen scientists are filling in knowledge gaps that we had previously,” said Caroline Juang, lead author of the paper and doctoral candidate in Department of Earth and Environmental Science at Columbia University.
With data from the Landslide Reporter and the Global Landslide Catalog, COOLR is now the largest publicly available global landslide database and should significantly improve NASA’s landslide hazard model, the Landslide Hazard Assessment for Situational Awareness. Past analysis by Kirschbaum and her colleague Thomas Stanley showed that landslides are likely to occur in areas that have previously experienced activity. Having more accurate accounts of such activity on the ground is critical to assessing future impacts. Satellite products such as topography, land cover change and precipitation can also help to further understand the distribution of potential landslide activity from space.
To participate in Landslide Reporter, visit https://landslides.nasa.gov. You can also follow the project on Twitter (@LandslideReport) and Facebook for updates.
NASA Earth Observatory image by Lauren Dauphin, using data from Juang, Caroline, et al. (2019). Story by Kasha Patel.