GNGTS 2014 - Atti del 33° Convegno Nazionale

24 GNGTS 2014 S essione 2.1 Spectrum Lab’s images of rumbles. Images of Spectrum Lab show very well the differences between the various typologies of rumbles, especially those similar to underground rolls of timbals, with or without earthquakes (Fig. 2b). Concerning the instrument elaborations of underground rumbles similar to rolls of timbals, we can observe a gradual increase and then decrease both in frequencies and intensity (Fig. 2b). This “crescendo” and “diminuendo” frighten animals more than other noises, because during this phenomenon animals crywith shrills Fig. 2 – a) Spectrum Lab. connected to Infrasound Meter; b) Spectrum Lab. elaboration (images of different underground rumbles and rumbles in air). a) b)