Landslides are one of the most widespread geological hazards on Earth, responsible for hundreds of deaths and billions of dollars in property damage per year. Landslides commonly occur with other natural disasters (e.g., earthquakes, floods) and leave the landscape prone to sedimentation, erosion, and further mass wasting. Remote sensing, the Global Positioning System (GPS), and geographic information systems (GIS) are now mature technologies that can be used to monitor landslides and landslide-prone areas with greater accuracy than could be accomplished previously with field reconnaissance alone.