Análisis de la probabilidad de ocurrencia de precipitaciones intensas y su aplicación a la predicción de movimientos de ladera en la tierra de Tramuntana (Mallorca)

Resumen

Intense rainfall episodes are the principal triggering factor of landslide phenomena in TramuntanaRange (Majorca Island). To accomplish a hazard analysis of landslide phenomenon, a probabilityanalysis of intense rainfall occurrence for different return periods has been realised. The completed annual sequences of data was fit with a Cumbel probability distribution. The Cumbel function,together with the related return period, allows to obtain the maximum rainfall values in 24 hoursthat can be expected for return periods of 5, 10, 25 and 100 years. Using a historic catalogue oflandslides, dated landslides have been correlated with intense rainfall episodes registered at theclosest meteorological station to the mobilised zone. This empirical correlation allows us to deducethat most of movements have been produced when maximum rainfall values in 24 hours reach 130mm, establishing this value as the statistical threshold triggering landslides. Analysis of the distribution of intense rainfall episodes along the Tramuntana Range allows us to predict, for a determined period of time, the areas with the greatest probability of surpassing the established thresholdthat could trigger a landslide.