A massive landslide devastated the community of Barangay Guinsaugon, Municipality of St. Bernard, Southern Leyte Province, Philippines, at about 10:30 local time on 17 February. The landslide occurred along the steep fault scarp of the Philippine Fault Zone (PFZ) (Figure 1a), a large and active tectonic structure that traverses the entire length of the Philippines [Allen, 1962]. Barangay Guinsaugon is located at the foot of the scarp, directly in the path of the downward moving mass of earth. As of 24 February, the landslide caused 122 confirmed deaths; 1,328 people still are missing. To assist in the search and rescue operations that followed the landside, a team of geologists and physicists from the University of Philippines (UP-Diliman, Quezon City) and Ateneo de Manila University conducted an investigation of this area on 21–25 February. The UP-Ateneo team provided technical advice on the geology, which included the identification of the type and characteristics of the landslide.