GNGTS 2013 - Atti del 32° Convegno Nazionale

below. But the same unusual animal behaviours before earthquakes with epicentre distances to SPSC progressively increasing were observed if there was also a progressive increase in the magnitude. The anomalous animal behaviours was observed with the following modalities: 1. particular vocal language in a tripartite sequence (in 3.2, 3.3); 2. non-vocal anomalous behaviour different from the usual pattern (in 4.1); 3. problems to health and safety (in 5.1). Particular vocal language in a tripartite sequence: animal alarms with shrills and high sounds. The acoustic perception of vocal alarms can regard a large area, it gives concise information and it is easier to note. The animal vocal alarm is a particular vocal language, usually directed to other members of the same species, sometimes to other species. It is an individual answer to the danger or a co-ordinate answer of the leading animal to the same danger. The first author has individuated a particular tripartite sequence in the vocal alarms of do- mestic animals and birds: phase A , lasting up to 2 hours, with shrills and high sounds, from 30 minutes until 10 hours before the earthquake; then, when cries stop simultaneously, phase B follows, with a strange and worry silence; finally phase C , with animal cries normally 20-40 seconds before the earthquake, a few times just 5-10 seconds before, generally stopping few seconds before the shock. The phase C is corroborated by the observations of other research- ers in case of other earthquakes (Rikitake, 1978, 1982). The vocal animal alarms beginning up to 10 hours before local earthquakes, sometimes before distant earthquakes if the future magnitude is great- er, are contemporaneous to the drastic reduction of variations in intensity and declination of the magnetic field and of radio- activity values. So, Figs. 1a and 1b resume an interesting rela- tion between seismic epicentre distances to SPSC, magnitude and percentage of unusual an- Fig. 1 – Percentage of vocal animal alarms in phase A and C, in relation to epicentre distance to SPSC. 61 GNGTS 2013 S essione 2.1