Earthquakes of volcanic origin (VT) represent a significant hazard in volcanic islands prone to landslides. We present a methodology to forecast large VT earthquakes during volcanic crises based on an algorithm that translates fluctuations of the level of seismicity into 10-day time windows of increased probability of a major event. This algorithm has been successfully applied during the 2011–2013 volcanic crisis at El Hierro (Canary Islands).