An Overview of the History and Potential of Multi-hazards in the Philippines

Many countries around the world are threatened not just by numerous natural hazards, but also the occurrence of multiple kinds of hazards such that they affect or interact with each other increasing their magnitude and propensity for damage. The Philippines, being one of the most hazardous countries in the world in terms of the frequency, magnitude, and variety of these hazards makes the study and assessment of multihazards in this region both uniquely interesting and imperative. There is a lack in coherent consolidation and systematic analysis of multihazard interactions in the Philippines, despite their historical occurrences and increased potential in the country leaving a significant portion of the population exposed to the exacerbating effects of compounding natural hazards. This study localizes published international multihazard interactions and frameworks to the Philippine setting and validates these based on recorded historical events or potential of occurrence based on the meteorological and geological setting. Considering a total of 21 natural hazards that may occur in the Philippines' geologic setting and tropical climate, there are 19 hazard cascades that have been observed and exist on record. A further 12 hazard interactions are hypothesized to have likely occurred, but no established studies or records exist due to the longer temporal scale of these processes. Finally, 9 hazard interactions are possible in the Philippine setting but have not occurred in the historical records and is likely a result of circumstance: these hazard interactions have simply not yet happened within the Philippines but may do so in the future. Hazard interactions with clear records involve earthquakes, tsunamis, volcanic eruptions, landslides, flooding, and storms; all of these occur with significant frequency and magnitude in the Philippines historically becoming the primary causes for death and damage to property during disasters induced by natural hazards. A more robust database is necessary for the general characterization of these interactions and their potential to do future harm in the Philippines and other countries with similar geologic and meteorological settings. This would also pave the way for well-informed policy crafting and disaster mitigation efforts meant to safeguard life and property.