Research Fellows Directory
Professor Katharine Cashman
University of Bristol
The hazards posed by volcanic eruptions affect human populations around the world, as illustrated in the past year by dramatic eruptions in Japan, Chile, Indonesia, Cape Verde, Iceland and Hawaii. My work addresses the processes that underlie two volcanic hazards - volcanic ash, which poses risks to civil aviation, agriculture and human health, and lava flows, which threaten infrastructure. By elucidating the underlying processes, my work provides critical information for development and testing of models used for ash transport and lava flow forecasts.
My work on ash involves detailed analysis of ash samples from recent (and well observed) volcanic eruptions. For example, documentation of the size, shape and density of ash particles produced during the 2011 eruption of Grimsvotn volcano in Iceland has shown that the unusually small size of the particles reflects the small size of gas bubbles originally in the melt, as well as rapid quenching of the melt by water from the overlying glacier. Importantly, we have also shown that surprisingly large ash particles can be transported much farther than model predictions, and that these same large particles can be re-suspended and re-transported by strong winds for years after the original eruption. We are currently working with researchers from the UK Met Office to incorporate these findings into their predictive models of ash hazards.
The effects of lava flows are not as far-reaching as those of ash hazards, but can be devastating for local infrastructure. Over the past several decades, there have been numerous attempts to mitigate against lava flow hazards using barriers and diversion channels of various forms. Motivated by our studies of how lava interacts with topography, we have performed laboratory experiments that provide new insight into design of lava flow barriers.
Interests and expertise (Subject groups)