The role of geomorphology, rainfall and soil moisture in the occurrence of landslides triggered by 2018 Typhoon Mangkhut in the Philippines

Abstract. In 2018 Typhoon Mangkhut (locally known as Ompong) triggered thousands of landslides in the Itogon region Philippines. A landslide inventory affected is compiled for first time, comprising 1101 over a 570 km2 area. The used to study geomorphological characteristics and land cover more prone landsliding well hydrometeorological conditions that led widespread failure. results showed mostly occurred on grassland wooded slopes clay superficial geology, predominantly facing east-southeast. Rainfall (Integrated Multi-satellitE Retrievals Global Precipitation Measurement, IMERG GPM) associated with compared 33 high-intensity rainfall events did not trigger regional 2018. Results show during coincided highest soil moisture values (estimated clays saturation point), according Soil Moisture Active Passive level 4 (SMAP-L4) data. Our demonstrate potential SMAP-L4 GPM data hazard assessment early warning where ground-based are scarce. However, other months leading up had similar or higher intensities also when soils were saturated landsliding, highlighting need further research into typhoons.