Overlaid with these nowcasts values are a Global Landslide Catalog(GLC) that was developed with the goal of identifying rainfall-triggered landslide events around the world, regardless of size, impact, or location. The GLC considers all types of mass movements triggered by rainfall, which have been reported in the media, disaster databases, scientific reports, or other sources. The visualization shows the distribution of landslides each month based on the estimated number of fatalities the event caused. The GLC has been compiled since 2007 at NASA's Goddard Space Flight Center and contains over 11,000 reports and growing. A new project called the Community the Cooperative Open Online Landslide Repository, or COOLR, provides the opportunity for the community to view landslide reports and contribute their own. The goal of the COOLR project is to create the largest global public online landslide catalog available and open to for anyone everyone to share, download, and analyze landslide information. More information on this system is available at: https://landslides.nasa.gov.
Landslides occur when an environmental trigger like an extreme rain event, often a severe storm or hurricane, and gravity's downward pull sets soil and rock in motion. Conditions beneath the surface are often unstable already, so the heavy rains act as the last straw that causes mud, rocks, or debris- or all combined- to move rapidly down mountains and hillsides. Unfortunately, people and property are often swept up in these unexpected mass movements. Landslides can also be caused by earthquakes, surface freezing and thawing, ice melt, the collapse of groundwater reservoirs, volcanic eruptions, and erosion at the base of a slope from the flow of river or ocean water. But torrential rains most commonly activate landslides.