The Time Clustering of Floodings in Venice and the Cantor Dust Method

Summary The catalogue of sea-floodings in Venice, accurately reconstructed for a period of 12 centuries (interval: 872–1996) has been analysed according to the Cantor Dust method. This provides a means of testing whether clustering in time is a scale-invariant process: if the fraction R of the intervals of length t containing flooding events is related to the time interval by: R∼t ^(1−D) , then the fractal clustering is occurring with fractal dimension D (0<D<1). The main result is the evidence for a gradual increase of the fractal clustering starting from 1914, when the soil subsidence of the lagoon basin determines an increase in its hydrodynamic response to the marine forcing with a gradual increase of flooding occurrences. Received October 1, 1996 Revised September 10, 1997