GNGTS 2013 - Atti del 32° Convegno Nazionale

producing E(t) = 6.1 hours and σ = 1.4 hours, anticipating of some hours the general animal precursors (Rikitake, 2003), but according to previous results for dogs and cats (Rikitake, 1982). Data from the phase C were excluded as they were considered to reveal animal agitation at the time of P-wave arrival. The early time distribution was also plotted with respect to the earthquake magnitudes and depths (see Fig. 2b). For dogs and cats behaviours, early times resulted independent from the earthquake magnitude, even if small earthquakes can alarm dogs and cats later with respect to greater earthquakes. Such small earthquakes have generally greater depths than small earthquakes which alarms dogs and cats around the average (see Fig. 2b on the right). Finally, great earthquakes influence dog and cat behaviours from any depths around the average early time. Non-vocal anomalous behaviour different from the usual pattern. When the rise in temperature, in the emission of gas, or in magnetic declination are great, we can observe evident anomalous animal behaviours, that are reactions to save theirselves. a. The most evident non-vocal animal behaviours is the advanced awakening from hibernation , probably due to a rise in temperature or to emissions of dangerous gas. Winter seismic activity is a better forewarning of the first shock because the precursor increase in soil and water temperature is well remarked. An increase in temperature of about 5-6 °C above the mean seasonal values at SPSC was often recorded before a seism. This can explain the premature awakening of animals in hibernation (bats, insects, amphibious and reptiles) and premature larva development (de Liso, 2010). This unusual animal behaviour is a short temporal term precursor, usually 12-15 hours before. Damages to people and animal health were observed in Torre Pellice, in connection with measured high radon values: especially dermatological effects were reported at SPSC when the radioactive emission was much higher than the local average values. b. Unusual flight behaviour with magnetic sudden variations: it is very important to individuate the right moment of the sudden magnetic commencement because it is the moment of unusual flight behaviour observations. SPSC observations confirm that when geomagnetic perturbation is not due to sun activity, but is due to the magnetic permeability variation of rocks under stress, we can observe unusual flight patterns of some birds and a few problems of balance for dogs, cats and also some human subjects. The sudden beginning can be followed, for up to a few days before a seism, by the variation of the absolute value of δ declination angle of local North-South axis and by the variation in the intensity of the geomagnetic field. In these occasions, the needles of the SPSC compasses showed a dampened oscillating motion around a new local North- South axes. At the beginning of δ oscillation, due to seismic activity, unusual flight behaviour was often noted. During this first moment it was noted that domestic animals are nervous and insects and arachnids are more aggressive, until magnetic variations are great. Among the animals that feel this magnetic variations more frequently, with anomalous flying patterns, there are female black-birds and bees (de Liso, 2010). c. Animals seek safety: in phase C farm animals seek safety from cow-houses, barns, pens or from other buildings collapsing. Animal shrills and their agitation can alarm people, so this animal behaviour has often saved people. For example, before the earthquake of April 2 nd , 1808, at 17:43 LT, with magnitude M = 5.7, with epicentre in Luserna San Giovanni a woman of San Germano and her sons were saved by the cows cries; also other people inside houses saved themselves, thanks to the agitation of their cows a few seconds before the seismic shock. But also during phase A this kind of anomalous behaviour can be observed. A local earthquake in Val Pellice, occurred on May 28 th , 2008, during a severe rainstorm, caused at the same time four landslides: two on Vandalino Montain, one at Rorà and one at Villar Pellice, killing four people. Half an hour before the seismic event and landslides, a male goat saved all his female goats, 63 GNGTS 2013 S essione 2.1