Socio-economic impact of the c. 800-500 yr BP. eruption of Mt. Pinatubo (Philippines) Hypotheses from the archaeological and geographical records

Before its worldwide famous awakening in 1991, Mt Pinatubo volcano erupted around 500 year BP. The impacts of this little known eruption are progressively coming to light with the discovery of archaeological sites and the study of oral and geographical records. Recent archaeological excavations have shown that tephra fall, pyroclastic flows and lahar onslaughts have probably led to the abandonment of major settlements on both sides of Mt. Pinatubo. The location of these archaeological sites and the toponyms on the east flanks of the volcano suggest a general redistribution of the population downstream toward lands newly reclaimed on the sea due to heavy lahar material deposition. These population movements did not occur on the west side of the mountain despite similar land reclaimation. Such topographic changes have deeply disturbed the socio-economic environment since it is hypothesized that extensive trade with China and other foreign 'countries' profited from the easy penetration of commercial vessels into the bays that have been filled up by lahar deposits. Finally oral memory records, such as legends and epics, help define the ethnic groups that have suffered from the eruption (e.g. Aetas, Kapampangans and Sambal). Understanding what happened 500 years ago turns very useful to anticipate the consequences of future events