This paper describes an interactive holographic simulation of volcanic eruption. The aim of the project is to use Augmented Reality (AR) technology to visualize different volcanic eruptions for public education, emergency training, and preparedness planning purposes. To achieve this goal, a 3D model of the entire Vulcano Island in Italy has been created using real elevation data. Unity game engine and Microsoft Visual Studio have been used to develop HoloVulcano augmented/virtual reality simulation application. The current version of HoloVulcano simulates normal and unrest situations, single and long lasting Vulcanian, Plinian, and Strombolian eruptions. HoloVulcano has been developed for Microsoft HoloLens AR device. Wearing the HoloLens, users can interact with the volcano through voice, gazing, and gestures and view different eruptions from different points in the island. HoloVulcano will be used for training emergency exercises and public education.