G. de Liso 1,2,3, A. Viotto 1 1. Seismic Precursors Study Center (SPSC), Torre Pellice (TO), Italy 2

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1 RUMBLES AND MISTPOEFFERS IN VAL PELLICE (WESTERN PIEDMONT) WITH AND WITHOUT EARTHQUAKES: A COMPARISON BETWEEN RADON 222 AND INFRASOUNDS MONITORING AND UNUSUAL ANIMAL BEHAVIORS G. de Liso 1,2,3, A. Viotto 1 1 Seismic Precursors Study Center (SPSC), Torre Pellice (TO), Italy 2 Istituto di Alta formazione artistica e musicale G.F. Ghedini, Cuneo, Italy 3 Voce Pinerolese, Pinerolo (TO), Italy Historical accounts and local people witnesses: a perceptive description of rumbles. The area of Val Pellice, located in western Piedmont, has a moderate seismicity, the recent classification of the seismic risk is 3S, but sometimes it is the theatre of earthquakes with magnitudes greater than 4 and 5 Richter, like the famous seismic event of April 2, 1808, with a magnitude recently estimated in 5.7 Richter. Regarding this latter earthquake, we have in Pinerolo an interesting relation of physicist G. Eandi and of captain L. Garola: they reported several observations during the long period of the following seismic storm, recording monitoring of chemical and physical parameters, unusual animal behaviors, anomalous atmospheric phenomena and seismic rumbles. Recently, the first author has added to monitoring of a few physical parameters also a research about local people witnesses of pre-seismic and seismic observations. It is very interesting to note that people living near the top of Vandalino Mountain or near Castelluzzo Peak, are better qualified to observe nature than people living in the centre of villages in Val Pellice: so during a seismic period, more observations by farmers are possible about anomalous animal behaviors and rumble or mistpoeffers. A statistic research on this topic is going on, but it is necessary to consider a more consistence of anthropic influences in centre of villages or little tows and different geologic morphology of areas of Castelluzzo-Bonnet, Vandalino s top, outer hamlets of Angrogna, Villar Pellice, Bobbio Pellice and Rorà. The no-profit association Seismic Precursors Study Center (SPSC), which collects these data, is located in Torre Pellice ( N, E, western Piedmont, NW Italy) at 699 m above sea level on Vandalino Mountain, not too far an abandoned iron mine, near a particular geological sanctuary (Compagnoni and Sandrone, 1981) of Castelluzzo. The area of Castelluzzo and Bonnet is rich in augen-gneiss, of eruptive origin, in biotite, ophiolite, zeolite, pechblenda and in Luserna Stone (gneiss). Around Castelluzzo Peak it is possible to observe a slight geothermal activity, with warm emission of sulphureous gases from rock cracks. It is also interesting to note in the local toponymy a few names that have evident connection with the presence of creeks with moderately warm water (Rive chaud, La Chauda ). This is also present in areas of Barge (Cuneo), near Bracco Mountain and near Rocca of Cavour. Both mountains have characteristics similar to those of Vandalino Mountain. In Val Pellice it is possible to hear frequently rumbles, and it is necessary to do an accurate description of them, on the basis of perceptive acquisition of their origin, direction and temporal term. Often these rumbles follow the rapid rise of grey-ochre clouds from ground depressions at the top of Vandalino, or near Castelluzzo, or near the Bric Bucie (Bobbio Pellice). The rumbles can be perceived as underground or air rumbles: a)- underground rumbles can be perceived as long underground thunders, as underground rolls of timbals or of kettle drums (not of drums without resonance case), as an underground landslide of big rolling stones, as underground mistpoeffers similar to far gun shots, but acoustically stifled, brontides, similar to the closing of a big underground door; b)- rumbles in air can sometimes perceived as single blows in air, without echo, or wind blows, with a temporal long term, or as far gun shots in air, with a long period of detonation. Taking into consideration the historical accounts of Eandi, it is important to underline that the observations of Eandi and Garola are similar to those reported by the first Author, in the same region, in Val Germanasca and Val Chisone. Moreover, there is an interesting citation in poetic verses of lyric aria La calunnia è un venticello, written by the composer Gioacchino 21

2 Rossini, contemporaneous of Eandi, that says: La calunnia è un venticello, un auretta assai gentile un tremuoto, un temporale che fa l aria rimbombar, come un colpo di cannone. Rossini was impressed by the chronicles of earthquakes in Val Pellice and the same words of Eandi are present in the lyric aria in Barbiere di Siviglia, whose librettist is Cesare Sterbini, that compares the progressive diffusion of slander to a seismic phenomena. In lyric literature this comparison slander-seismic phenomena-volcanic explosion is often present, according to a popular knowledge concerning seismic and pre-seismic phenomena. With reference to rumbles similar to underground rolls of timbals, we must observe another comparison with musical language: these rumbles have a progressive rise in frequencies and intensity, as in a Beethoven s crescendo and diminuendo or as in a crescendo rossiniano, we can better observe this characteristic in images of infrasound monitoring, thanks to Spectrum Lab elaborations. Often, in these cases there are contemporaneous earthquakes. Generally, in the case of underground rumbles, there is a contemporaneous little local trembling of the ground, not necessary an earthquake, that often happens 8-15, sometimes 20 hours before earthquakes with epicenter km far from Torre Pellice, generally in the area of Cuneo, of Barcelonette or of Brianḉon (France); if there is an important, long storm of shots and rumbles. So we can consider this local trembling following underground rumbles on Vandalino as a phenomenon connected to another future seism with a farther epicentre. In a few cases, rumbles similar to gun shots (observed in Torre Pellice and in a big area of Piedmont and Liguria) happened after earthquakes with magnitude of 4.6 Richter (July 2011), and after a 5.0 Richter (April 2014) in the French Southern Alps, but one time the same rumble happened in Val Pellice 40 minutes before a seism with a magnitude of 0.8 Richter, near Acceglio (July 2012). Sometimes, rumbles and mistpoeffers are localized very well in Castelluzzo Peak, in a small underground area of m of height: below this area you can hear the rumble above it, while above this area the rumbles can be heard from below. People living near Castelluzzo have the same perception. Often, rumbles, localized in Rorà s area or in the nearby Frioland Mountain, are followed by a local seism after minutes, if there is a sequence of rumbles after the first one. In the consideration of eventual connections between rumbles as pre-seismic or post-seismic phenomena and earthquakes, it is important to take into account the difference of geological micro-zones. Then, it is necessary to distinguish rumbles and brontides where no earthquake follows from the rumble of a seism taking place. In the area of Rorà and Barge there are several gneiss mines, so it is important to differentiate natural rumbles from mine detonations: explosion rumbles of mines have higher frequencies than natural rumbles, they are very short and animals (generally dogs and birds) always cry after these detonations. In the case of natural rumbles and brontides, animals cry seconds before them, but a wider number of animal species is interested, crying together: dogs, donkeys, cows, cocks, chickens, crows, buzzards, night-birds of prey. Concerning night-birds of prey, they usually scream during the night, but in the case of brontides they cry also during the morning or the afternoon. A musical sensibility in acoustic perception can assist while considering little differences in the tonal language of animals during their normal life or during situations of alarm. In case of rumbles and brontides followed by earthquakes, vocal animal alarms are like those observed in phase C, before earthquakes (de Liso and Fidani, 2014; de Liso et al., 2014); vocalizations are more excited and, bearing in mind dog cries, we can hear melodic dissonant intervals. In case of rumbles and brontides without subsequent earthquakes, the shrills are less frequent, but always excited (generally high and with melodic dissonant intervals) and the temporal period of vocal alarm is shorter than in phase A (several hours before earthquakes). Infrasound monitoring: instrumentation, monitoring modality, Spectrum Lab s images of rumbles. Instrumentation. In SPSC an infrasound monitoring by an Infrasound Aetech Meter 22

3 has been active for two years, with the following characteristics: Power voltage: Battery 12 volt Dimensions: 300x210x35mm, 1 kg. Degree of protection: IP 44 USB range of measures: 0-20 Hz. VCO range of measures: 0-35 Hz. Stabilization time: S. Graphic display: USB interface Acoustic gauge: B.F. exit: Hz. Central frequency: 1780 Hz. Battery life: 6 hours Sensor: Infrasounds pickup of Aetech Infrasounds Monitor The Infrasound Meter is placed in SPSC basement of the first author s house, as we can see in Fig.1. The sensor of the infrasound detector is placed near a wall, at a distance 15 cm from it (de Liso et al., 2013). Fig. 1 Location of the infrasound Meter. Monitoring methodologies. The monitoring, continuous and connected with a computer, is intentionally placed to this day in the first author s house, near a forest, in an area with little anthropic disturbance. Normal family life gives the first author the possibility of discrimination between anthropic and natural sounds, rumbles and so on, thanks to images formed by the Spectrum Lab. Spectrum Lab, connected to Infrasound Meter, synthetically gives her information about frequencies, intensity in db and seconds (Fig. 2a). Thanks to her acoustic perception (windows are left open during these studies), contemporaneous to the observations of Spectrum Lab, she can note the different origins of the sounds and the causes generating them. To this research methodology with Infrasound detector, observations with a Geiger Detector on Castelluzzo and near the summit of Vandalino Mt. are also added. The next project of SPSC of an infrasound monitoring in an outside place with a low anthropic disturbance, but this is now not technically easy. Aetech Detector gives also continuous data in volt/s and in Hz/s (Fig. 2a). 23

4 Sessione 2.1 GNGTS 2014 a) b) Fig. 2 a) Spectrum Lab. connected to Infrasound Meter; b) Spectrum Lab. elaboration (images of different underground rumbles and rumbles in air). 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 cry with shrills volume :51:35

5 more intense than during other rumbles with or without earthquakes. Perhaps the increasing in frequency and intensity gives the animals the sensation of a terrific danger, that pounce as a predatory on a quarry. Generally animals begin to cry when the frequency values are around Hz, but only when these low frequencies rapidly rise. In fact, when natural (creek noises) or anthropic noises or sounds with low frequency values are rather constant, animals are calm. It is interesting to observe some circular and oval figures in spectrum analysis of rumbles when the increase and the following decrease in intensity and frequency are rather uniform. In Fig. 2b we can observe a spectrum figure as a Moorish arc. Animals (those mentioned in chapter 1) always shrill before the rumbles just mentioned above, whatever they may be, but rumbles having a spectrum elaboration with geometrical forms similar to circles, ovals or Moorish arches, when are not followed by a seism, infuse in animals a great fear that expresses itself in anomalous behaviors with high shrills preceding the rumbles. In this instance, animals start to shrills when the frequency of such rumbles is between 3 and 5 Hz. Instead other typologies of rumbles, underground or in air borne, always preceded by animal high cries, induce animal to seek safety by taking to flight, if this is possible. Perhaps, regarding other typologies of rumbles there is a greater association with earthquakes and landslides. Rise in Radon emission, eventual seismic events and rumbles increasing. In an area rich in augen-gneiss, of eruptive origin, and in pechblenda, with also emission of gases, often warm before seism, a continuous Radon 222 monitoring can provide good information about underground gases or water shifting, eventual seismic precursor (de Liso, 2010; de Liso et al., 2011). The instrument for the Radon monitoring is a Radon-meter detector (Geoex, model 1027), located in SPSC basement, as we can see in Fig. 1. To this day, we have often observed before local earthquakes a rise in Radon mean values, two, three days, sometimes one week before. In the case of earthquakes with magnitude over 3.5 Richter we have sometimes observed a few variations of water-course of creeks in Val Pellice, this happened also for Biglione creek. In these cases, a remarkable variation of Radon mean values was recorded in SPSC. For example, one week before the seism of April 7, 2014, with magnitude 5.0, depth of 5 km and with epicenter distance of 25 km from Torre Pellice, we recorded in SPSC Radon values inferior to the average, contemporaneously to a sudden reduction in the flow of Biglione creek (near SPSC). A reconnaissance on the area above SPSC by the first Author has shown her a variation of the water flow of Biglione creek above Castelluzzo: the creek became hollow in a large transversal crack, and the noise of the water was similar to the one of a waterfall. During the same time, Biglione s water flow near SPSC was much reduced despite the rains just occurred, Radon mean values in SPSC basement were 81,4 Bq/m 3, lower than the average local values before a seism. We can suppose that creeks that became hollow in cracks, can create cavities, which can changes Radon carriers, underground movements of gases and the production of different typology of rumbles. For example, in the week before the earthquake of April 7, 2014, a new Radon monitoring (with Geoex Radon dosimeters) in a second house 300 m from SPSC, that had showed for the two months before Radon mean values of 14.8 Bq/m 3, recorded mean values of Bq/m 3. During this same week, this latter house had the basement flooded, so also two houses located nearby. The inverted situation of Radon mean values between SPSC and this house persists at this day, even if in SPSC basement Radon mean values are gradually returning at higher average values, luckily not as in December 2013 (Fig. 3). In this instance, together with the anomalous emission recorded in the basement of SPSC (1517 Bq/m 3), an important increase in temperature occurred together with numerous rumbles (more than 50) a day before a local seism (2.6 Richter). 25

6 Fig. 3 Radon 222 emission in SPSC, October-December, Radon is a heavy gas, so it can be pushed up by warmer gases, or by underground water. At this day, we have noted that an increase of Radon mean values can forewarn a seismic period, not always immediately, but a sudden increasing of Radon emission is always accompanied by a temperature rise and by a rise in frequency of rumble events, with or without earthquakes. The sudden increasing to the high value of 1517 Bq/m 3 on December 2, 2013, was simultaneous with an increase in temperature (over 5 the mean) in SPSC basement and was preceded by several rumbles, similar to underground rolls of timbals, and to far gun shots, but acoustically stifled. The brontides, similar to a closing of a big underground door were numerous, especially at the beginning of the Radon increasing. They remind some kind of floating pistons, tossed by underground water. These brontides, in fact, at the beginning of the long sequence of rumbles, are rhythmical enough, with short period of constant intervals of events. Actually, on December 3, 2013, a little earthquakes happened in Cuneo s area, with a magnitude of 2.6 Richter. But we must not think that there can be a possible correlation between high average values of Radon emission and high values of magnitude of the future earthquake, because the valuations based on graphic analysis do not confirm this. In Fig. 3, rumbles happened just before every sudden increase in mean values, with animal alarms second before every rumble. Conclusion. We can resume the following: a- The interesting geological structure of Valle Pellice, especially of Vandalino Mountain and Castelluzzo Peak presents good opportunities of development to the research on seismic precursors; b- During pre-seismic phase, the increases in Radon emission, in temperature values and in the frequency of rumble events are connected together; the future earthquakes can happen not always soon, but these parameters can be good precursors, with short, medium and long forecast period; c- Always with a sudden increase in Radon emission and in soil temperature there are rumbles of different typology: 1-underground rumbles similar to underground thunders, to underground rolls of timbals, to an underground landslide of big rolling stones; there are also mistpoeffers similar to far gun shots, but acoustically stifled, brontides, similar to a close of a big underground door; 2- rumbles in the air similar to single blows in air, without echo, or wind blows, with a temporal long term, or to far gun shots (rarer); d- Animals always give alarms before rumbles, with or without following earthquakes; 26

7 e- Animals give alarms before local earthquakes, but on this topic there are many particular observations to do; f- Every typology of rumble is very differentiated by infrasound monitoring and by Spectrum Lab analysis. Acknowledgments. C. Fidani, G. Martinelli, L. Pierotti, A. Riggio, R. Sandrone, A. Vaio References G. de Liso; 2010: Caratterizzazione del territorio nell individuazione dei precursori sismici locali nel Piemonte Occidentale in 29 Convegno Nazionale GNGTS, Gruppo Nazionale di Geofisica della Terra solida, (Trieste Novembre 2010, Palazzo dei Congressi della Stazione Marittima, Riassunti estesi delle comunicazioni, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) //pp G. de Liso G.; Lattarulo F., Viotto A.; 2011: Piezonuclearità, piezoelettricità e piezomagnetismo delle rocce di gneiss e caratterizzazione territoriale della fenomenologia sismica nel Piemonte occidentale, nuove prospettive di studi (30 Convegno Nazionale GNGTS, Gruppo Nazionale di Geofisica della Terra solida, Trieste, Novembre 2011, Palazzo dei Congressi della Stazione Marittima, Riassunti estesi delle comunicazioni, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) // pp G. de Liso, C. Fidani, A. Viotto; 2013: Multiple-parameter and seismic precursory phenomenology in unusual animal behaviour in Western Piedmont (Atti del 32 Convegno GNGTS di Trieste 2013, Tema 2), // pp G.de Liso G., C. Fidani, A.Viotto; 2014: Unusual animal behaviour before earthquakes and multiple parameter monitoring in Western Piedmont, Earth Science 02/2014, 3(1), 14-25, doi: /j. earth G:.de Liso, C. Fidani; 2014: Seismic Precursory Phenomenology in Unusual Animal Behaviour in Val Pellice, Western Piedmont, in Comparison with Anomalies of Some Physical Parameters,Open Journal of Earthquake Research, 2014, 3, Published Online February 2014 R. Compagnoni R., Sandrone R.; Lineamenti geo-petrografici delle Alpi Cozie Italiane tra la Val di Susa e la Val Po, Federazione Piemontese di Mineralogia e Paleontologia, Torino,