Landslide hazard assessment and mitigation measures in Philippine geothermal fields

Simple, yet reliable, field criteria have been developed and are being used to qualitatively assess slope instability and slope failure potential in Philippine geothermal fields. Based on a hazard assessment classification of slopes along corridor facilities, sites for implementation of engineering measures are selected. Two case studies are presented. In Mindanao field, the “very high-risk” classification of an area resulted in the installation of pipe shelters, which subsequently shielded a section of a pipeline from landslides. Follow-up monitoring is also conducted using cheap, locally fabricated tools, such as surface extensometers. This is being done in Leyte field, where a landslide has threatened a transmission line tower.