Predicting Volcanoes - for iPod/iPhone

The Open University's researcher in volcanoes, Hazel Rymer explains why the Poás volcano in Costa Rica is her favourite, and how evidence form previous experiments there has lead her to believe there may be an environmental crisis - similar to one in the 1990's - on it's way. There have been changes in gravity above Poás, and Hazel talks us through some experiments she will be undertaking in the future.