A new and more comprehensive approach to volcanic hazard assessment was developed during the IDNDR and in the early phase of the ISDR. This new methodology involves, not only traditional hazard mapping, but also studies of environmental impacts and investigations of social, economic and cultural aspects of human vulnerability (Chester et al., 2002). The present study represents the application of this new methodology to Fogo Volcano, on São Miguel Island in the Azores.
Fogo is the largest of three active central volcanoes on the island, and dominates its central region. It has a complex morphology, with a summit caldera formed as a result of numerous collapse and explosive events that have characterised the final stages of an eruptive history of more than 200 ka. The most recent event was a sub-plinian eruption that occurred in 1563. Historic records and recent instrumental data also testify a history of intense seismic activity, which includes paroxysmal events such as the 1522 earthquake - which killed around 5,000 people, and recurrent low to moderate magnitude seismic swarms that have dominated the last few decades.
Volcanic and seismic histories of the volcano have allowed hazard scenarios of seismo-volcanic events to be developed. These, however, are supplemented by studies of slope instability and extreme weather conditions, which also present a significant threat to people, housing and livelihood on São Miguel. Conflation of these investigations has allowed us to establish much more comprehensive hazard scenarios than is usually the case in the study of active volcanoes.
To understand and evaluate the impact of these scenarios on the people of São Miguel, a detailed demographic and socio-economic study has been carried out, along side the evaluation of physical hazard. In particular, we have undertaken a detailed survey of the roads of the area and their effectiveness as evacuation routes, with special attention being paid to the stability of bridges and slopes.
In conclusion, we discuss some of the constraints on successful hazard management that are highlighted through the application of a methodology, which integrates physical and socio/economic perspectives on hazard management.