Landslides are one of the most pervasive hazards in the world, causing thousands of fatalities and billions of dollars in damages each year. Intense or prolonged rainfall is the most frequent landslide trigger, but seismicity, river undercutting, freeze-thaw processes, and human activity can also cause extensive and devastating landslides. While landslides are often small in area, with significant triggering events, they can be widely distributed across an area and result in runout or mobilization of debris that can extend for miles. Understanding where and when landslides have occurred in the past and where they may occur in the future is extremely challenging because of the lack of ground-based sensors at the landslide site to provide both triggering information (e.g. rainfall intensity and duration), and the timing and extent of the mass movement events. Remote sensing information provides critical insight to identify landslide activity, characterize the triggering patterns of these events spatially and temporally, assess the surface conditions for potential activity, and support the full cycle of disaster risk assessment.
There are several ongoing activities to address landslide hazard assessment using remote sensing data. The Committee on Earth Observing Systems (CEOS) Disaster Working Group (http://ceos.org/ourwork/workinggroups/disasters/) is starting a new Landslide Pilot that will consider landslide detection, mapping, and monitoring to support situational awareness and response to landslide disasters in several study areas (link will be up later this fall). There are also several US-based initiatives to monitor landslide activity for key active areas (http://landslides.usgs.gov/monitoring/). There is also a NASA-developed Global Landslide Catalog (GLC) that has information on rainfall-triggered landslides compiled from media reports, disaster databases, etc. from 2007-present (current placeholder URL: http://ojo-streamer.herokuapp.com/).