Forecasting potential outcomes of volcanic unrest and activity is usually associated with high levels of scientific uncertainty. Knowing whether particular volcanic unrest will end with an eruption or not implies reliance on scientific knowledge on how the volcano has behaved in the past and on how monitoring signals can be interpreted in terms of magma movement. This may be relatively straightforward in volcanoes that erupt frequently, but may be much more challenging in volcanoes with long eruptive recurrence intervals or even more in those without historical records. The dramatic consequences that wrong interpretation of volcanic unrest signals may have should persuade volcanologists to understand that communication among them during an emergency is crucial. Consensus to quantify scientific uncertainty must be reached, in order to provide the decision maker with a simple and clear forecast of the possible outcome of the volcano reactivation. Unfortunately scientific communication during volcanic emergencies is not an easy task and there is not a general agreement on how such communication should be conducted, not only among scientists, but also between scientists and other stakeholders (e.g. decision makers, media, local population). The critical questions here, as occurs with other natural hazards, are how to quantify the uncertainty that accompanies any scientific forecast and how to communicate this understanding to policy-makers, the media and the public. In addition to scientific advance in eruption forecasting, future actions in volcanology should also address improving management of uncertainty and communication of this uncertainty.
One of the most challenging aspects in the management of volcanic emergencies is scientific communication. Volcanology is by its nature an inexact science, such that appropriate scientific communication should convey information not only on the volcanic activity itself, but also on the uncertainties that always accompany any estimate or forecast. Deciphering the nature of unrest signals (volcanic reactivation) and determining whether or not an unrest episode may be precursory to a new eruption requires knowledge of the volcano's past and current behaviour to help establish future behaviour.