Noise-induced critical phenomena:: a case study

The NE flank of Stromboli volcano referred to as Sciara del Fuoco (SdF), due to its slope instability and the strombolian type activity is subject to landslides. Analysis performed on ground displacements measured at the SdF by an automatic monitoring system referred to as THEODOROS (THEOdolite and Distancemeter Robot Observatory of Stromboli), have shown that the recorded cumulative probability of displacements are power-law distributed. The volcano flank seems affected by movements that could be explained using a mechanical model. The proposed model consists of a slider mass driven-noise placed on an inclined plane with the same incline angle of the SdF (theta=36.8). The aim of our study is to investigate the effects of noise on the cumulative size distribution of the proposed model. In particular we show that appropriately choosing the range of variation for the intensity of a Gaussian distributed noise source with zero mean it is possible to model the observed displacements. This is an example of noise-induced critical phenomena.