 Although Muckelroy considered both natural processes and human activity in his model, subsequent research has mainly expanded the environmental factors and there has been little published on the human processes.A paper by Martin Gibbs in 2006, expands Muckelroy's model to consider human behaviour at the time of the disaster and the long term relationship between people and shipwrecks.This model uses studies of humans involved in disasters to characterise the human activity into phases around the time of the wrecking.