Impact evaluation of potential volcanic plumes over Spain

• Transport of simulated volcanic ash to Spain
• Weather patterns associated to the arrival of volcanic plumes
• Impact occurrence probability
• Pathways and time transport
• Dispersion of the volcanic plumes in selected events

The volcanic ash transport to Spain has been investigated as a part of a broader scale forecast system. Based on a double criterion, distance and eruptive history, four volcanic areas potentially affecting Spain have been investigated: Azores Islands (Portugal), Canary Islands (Spain), Iceland, and southern Italy. The paths of simulated plumes have been computed from daily forward trajectories for the period 2005–2012 using the volcanoes' locations as departure points. The frequency of impact of the hypothetical plumes has been calculated for eight regions in Spain. The probability in all cases is low. Portuguese and Spanish volcanoes present the highest probability in the warm season (~ 3.5%); the volcanic ash from Iceland would be expected to arrive mainly in the cold season (< 1.5%). Italian volcanoes show the lowest probability (< 0.5%). The weather patterns associated to the arrival of volcanic plumes from the four volcanic areas have been identified. The mean times required for the ash plumes to reach Spain from the Canary Islands, Azores Islands, Iceland, and Italy are 40, 42, 57, and 61 h, respectively. The HYSPLIT model has been used to study the volcanic plumes' dispersion and concentration fields in three aviation reference atmospheric layers. Values with high hazard for aviation have been obtained over Spain following the hypothetical eruption of a Canary Islands volcano. Fields of medium hazard would be found over Spain after a Portuguese volcano eruption. The volcanic ash from Icelandic volcanoes shows low hazard, while Italian volcanoes indicate a null hazard in most cases.