The type of volcanic explosive activity known as Strombolian is characterized by repeated, low energy, explosions and is named after the volcano where such activity has persisted for around 2000 years, i.e., Stromboli in the Aeolian Islands (Italy). Because activity is guaranteed, Stromboli represents an excellent laboratory where measurements of the explosions can be made from safe, but close, distances. This allows us to understand what causes the volcanic explosion and then how the erupted cloud of bombs, ash and gas moves. Measuring these properties alone would be an advance itself, but it will also allow us to further understand how and why a volcano erupts and how its potentially hazardous explosive products are dispersed. This project will be coordinated with other scientists from the University of Florence and in collaboration with the Italian agencies responsible for monitoring this volcano. It is expected that the results can feed back to help improve the understanding of the explosive behavior of US volcanoes, where a new vent opening on Kilauea that required the shut-down of a section of the Hawaii Volcanoes National Park, is degassing in a very similar manner to Stromboli's open vents. The team will also directly feed results from this research into the education and training of our University of Hawaii students who will work with, and learn from, the collected data.
To achieve our aims it is planned to combine a number of new technologies, such as hand-held thermal infrared cameras. These allow us to take thermal images of the plume at frame rates of up to 40 frames per second as it ascends from the vent. In addition, they will use a new, portable, generation of sulfur dioxide gas sensors that enables tracking of the variation in gas emission during each explosion. Simple numbers such as the velocity, volume and density of the explosion cloud are extremely hard to measure but are pivotal in predicting how a cloud will rise and drift. These new technologies will provide essential data regarding these key properties. Another key piece of evidence in determining what causes the explosions is locked in the scoriae that are thrown out during the explosion. Their textures (in terms of bubbles and crystals) contain precious information about the conduit dynamics that led to the explosion. At the same time the explosion produces a sound, as well as earth tremor, that also tells us about the source properties of the explosion. Thus, it is also planned to sample these scoriae, and combine their information with sonic, seismic, thermal and gas sensor data to understand how the explosion is generated, how the cloud ascends the conduit and, then, how it exits the vent.
