By Lara Smale
Volcanologically speaking, 2015 was an exciting year for new eruptions, and marked several significant anniversaries of volcanic disasters. Most commemorated perhaps was the bicentennial of the largest eruption in recorded history, at Tambora, Indonesia, but it was also the 35th anniversary of the Mt St Helens eruption that killed 57, and the 30th anniversary of the Nevado Del Ruiz disaster that killed 23 000 people and wiped the Colombian town of Armero off the map. Mt St Helens registered on the Volcanic Explosivity Index as a VEI 5 event, whilst Nevado Del Ruiz was orders of magnitude smaller at VEI 3. Why then did so many more people die? Fundamentally the answer is this: quality of communication
In the build up to an eruption volcanoes usually generate signals1 that they are entering a new phase of activity, such as increases in seismic activity, ground deformation, and changes in gas chemistry. As yet there is no precise and reliable way to predict an eruption, so in an ideal emergency management scenario scientists monitor these precursors to assess the likelihood of an eruption and provide a regular flow of information about the hazard to ‘decision-makers’. These are the organizations responsible for assessing the risk to a population, and making strategic decisions such as evacuation. Together these groups prepare official information for the media, who then broadcast warnings to the public. How people perceive the threat, regardless of whether they are a monitoring scientist, emergency manager or member of the public, depends on the quality of the communication they receive, and determines whether or not they take appropriate risk-reducing action.
Volcanic crises are highly complex scenarios scientifically, socially and politically (see Dante’s Peak!). Volcán Ruiz erupted on 13th November 1985 with a small magmatic eruption, forming hot flows of gas and rock called pyroclastic density currents. These currents melted the overlying ice cap, generating volcanic mudflows called lahars. Just before midnight, these cement-like slurries of volcanic material and water decimated the city of Armero 40km away, killing almost all its inhabitants. Scientists had realised that lahars posed a serious threat to the city, but poor communication in the months and hours before the eruption led to a confused emergency response, resulting in devastating loss of life. Looking back at past eruptions such as this one gives us the opportunity to examine the importance of communication in preventing such disasters.
Precursor signals had been recorded at Ruiz for nearly a year before there was any explosive activity. Such prolonged crises are problematic – long-term forecasts have a high degree of uncertainty, making it difficult for scientists to provide information that decision-makers can use to decide on a course of action. At Nevado del Ruiz this situation was exacerbated further by disagreement between the two scientific groups monitoring the volcano over how much of a hazard the volcano posed2. This resulted in conflicting information being presented to decision-makers. Consequently, some were skeptical about the impending threat and the confusion delayed the implementation of mitigation measures.
One of the most dangerous things during a volcanic crisis is misinformation. At Armero the authorities were worried that talk of an eruption would devalue real estate and cause panic, so articles were published in the media reassuring the public that there was no danger. These directly contradicted messages from some scientists and emergency managers, stating the volcano had the potential to erupt. The mixed messages caused confusion amongst the public leaving them completely unprepared. Even the Mayor was quoted as saying “…people have lost confidence in the veracity of information and have commended their fate to God” (Cosnigna, 15th October 1985, pp. 1642).
What finally sealed Armero’s fate was the overcomplicated emergency management structure. This led to ineffective communication between the different bodies involved in the emergency response, and when the emergency management was made aware of an escalation in activity several hours before the lahars hit, there was a complete breakdown in the communication chain. Ultimately, no formal alert or evacuation order was given.
The communication problems encountered at Nevado del Ruiz are by no means unique to this eruption, and the contrast with Mt St Helens highlights the influence communication has on the outcome of a volcanic crisis. Both volcanoes awoke after decades of repose, but at Mt St Helens, the communication of hazard with one scientific voice and the frequent, consistent information provided by an official source to the media and public were key to saving thousands of lives3.
Communicating Against the Odds
Lessons have been learned from past events and a protocol4 now exists for professionals communicating risk during an emergency. We have a much better understanding of how people interpret risk, and tools such as Early Warning Systems are being developed.
But many challenges remain, such as how to communicate scientific uncertainty to the public and to decision-makers. New challenges are also emerging, such as the role of social media, which could prove useful for disseminating warnings but may also provide new avenues for misinformation to circulate. Effective communication between monitoring scientists, decision-makers, the media and the public is absolutely essential in preventing disaster. We must take care that all our scientific and technological advances aren’t rendered futile by something so seemingly simple as communicating information.
1. Sparks, R. S. J. (2003). Forecasting volcanic eruptions. Earth and Planetary Science Letters, 210(1-2), 1–15.
2. Voight, B. (1990). The 1985 Nevado del Ruiz volcano catastrophe: anatomy and retrospection. Journal of Volcanology and Geothermal Research, 44, 349- 386.
3. Newhall, C. G., & Punongbayan, R. S. (1996). The Narrow Margin of Successful Volcanic-Risk Mitigation. In R. Scarpa, & R. I. Tilling, Monitoring and Mitigation of Volcano Hazards (pp. 807-838). Springer Berlin Heidelberg.
4. IAVCEI Subcommittee for Crisis Protocols (1999). Professional conduct of scientists during volcanic crises. Bulletin of Volcanology , 60, 323–334.
5. Haynes, K., Barclay, J., & Pidgeon, N. (2008). Whose reality counts? Factors affecting the perception of volcanic risk. Journal of Volcanology and Geothermal Research , 172, 259-272.
6. Kilburn, C. R., Solana, C., Michnowicz, S., & Edwards, S. (2012, November 19-23). Delivering hazard information: from misunderstandings to mayhem. Poster, Cities on Volcanoes 7, Colima .
7. Solana, M. C., Kilburn, C. R., & Rolandi, G. (2008). Communicating eruption and hazard forecasts on Vesuvius, Southern Italy. Journal of Volcanology and Geothermal Research, 172, 308-314.