Early warning for the 1991 eruptions of Pinatubo volcano : A sucess story

The success or failure of a warning system can be gauged in terms of the number of lives (and value of assets) lost to or saved from a disaster causing event. In these terms, the early warning system used to Pinatubo Volcano in 1991 can be considered a success story b- the death toll of 250 - 300 out of the 20 000 immediately at risk was small despite the magnitude and violence of the eruption which was one of the world's biggest eruptions this century. This success can be attributed to a number of factors: early detection of the unrest, timely identification of hazards and delineation of vulnerable areas to them, successful application of state - of - the - art monitoring and surveillance techniques, accurate prediction of the most destructive phase of the eruption, timely issuance and dissemination of easily understood warnings, prompt action of key civil defence officials and disaster response workers , and timely evacuation of majority of the inhabitants at risk. What made the Pinatubo story a classic are not only its success factors but also its near - misses - the things that could easily have gone wrong but luckily did not, which provide valuable lessons for developing warning systems in particular and volcanic risk mitigation plans in general. The positive aspects of the experience highlighted the value of the following: state - of - the- art monitoring equipment and techniques, international cooperation based on mutual respect, sustained intensive public education on volcanic hazards; active involvement of selected scientists as the designated spokespersons in awareness promotion and warning dissemination; open and speedy communication lines between the science people on one hand and the civil defence officials on the other; and good relations between scientists and the media. He near - misses or potentially negative aspects of the experience underscored the need to conduct geologic data base studies and hazard zonation on all active volcanoes long before the onset of unrest. We were lucky because Pinatubo gave us sufficient lead time to conduct reconnaissance geological studies and mapping of deposits of its past eruptions, thus enabling us to forecast the life - threatening hazards when it decide to erupt and to warn/educate concerned sectors into taking appropriate protective actions. We know that we will not always be as lucky. Hence, efforts will now be focussed on detailed studies and mapping of the unmonitored active volcanoes and on conducting in communities - at - risk an Pinatubo education campaign that would erode their indifference, scepticism and hostility to long - term action plan for volcanic disaster mitigation. (AU)

Mitigation volcanic disasters

The basic foundation for mitigating volcanic disaster is anticipation. Being able to foresee what active volcanoes will do or are capable of doing whenever they arupt will definitely minimize or prevent loss of life and property. There are, therefore, many steps involved in mitigating disasters from volcanic eruptions and their attendant primary and secondary hazards. Some of these are to be implemented long before the onset of eruptions , others to be implemnets days or weeks before the eruptions, and others still to be done during and after volcanic unrest, In capsulized form, the approach we are successfully applying in the philippines, as in the June 1991 eruption of Pinatubo Volcano and the 1993eruption of Moyon Volcano, involves the following: identification of actives volcanoes in the country; sestablishmend of monitoring stations per active volcano; conduct of basic studies to determine the nature and characteristics of the volcano's eruptive behavior; hazard assessment and zonation; hazards awareness and preparedness promotion before and during volcanic unrest; selection and designation of escape routes and evacuation centers; team work and proper delineation of tasks and coordination among disaster response agencies; determination of the lone source of information about a developing or ongoing unrest; complete monitoring and documentation of volcanic crises; determination of the end of volcanic unrest; promotion of volcanic hazards - constrained land use planning around active volcanoes.(AU)