Images of ancient Calabrian-Sicilian earthquakes from a stereoscopic viewer of the early 20th century. The ethics behind a natural disaster photo-gallery

This research was inspired by an old stereoscopic viewer from the early 1900s, containing 42 glass slides depicting scenes from two Italian earthquakes that struck Southern Calabria and Eastern Sicily in the years 1894 and 1905, causing hundreds of deaths, but whose memory was blurred by the subsequent, great earthquake of the Messina Straits of December 28, 1908. The sequence of three-dimensional images shown by the viewer gave a deep and realistic visual impact to scenes of collapses, debris, and victims, arousing feelings of dismay. In this work, we describe the viewer apparatus; the places depicted in the stereoscopic plates, and the seismic phenomena that caused the disasters. But above all, we investigate the social and cultural aims that pushed to show the effects of local earthquakes through this kind of primitive multimedia mechanism. We exclude that the viewer, with its photographic equipment, was merely an instrument of entertainment. We rather assume that it carried out an educational task. The repetition of the sequence of tragic images of earthquakes through the stereoscopic viewer had the purpose of contributing to give awareness of the looming seismic risk and to accept rationally those recurring disasters.


Introduction
A stereoscopic viewer from the early 1900s, equipped with 42 transparencies on glass plates, shows the images of two earthquakes in Southern Calabria and Eastern Sicily, that can be considered forgotten by the general public.
We refer to the earthquakes that occurred in the years 1894 and 1905, destroying some small towns and causing hundreds of deaths, but whose memory was overshadowed by the subsequent great earthquake of the Strait of Messina, on 28 th December 1908 (about 80,000 deaths).
The stereoscopic viewer was a wedding gift for a couple of young spouses of the Messinese bourgeoisie, who got married in 1904, and it was placed on a table in the living room where the newlyweds used to gather friends. It was a taxiphote model, a crafted but faithful copy of a French variant of stereoscopic viewers in vogue at the time of the Belle Epoque (Figure 1, 2). Franco Foresta Martin et al.  The instrument consisted of a wooden box equipped with two eyepieces in front of which it was possible to position photographic transparencies realized in such a way to give a three-dimensional view of the scenery. It was a sort of augmented reality ante litteram. The sequence of three-dimensional scenes of collapses, debris, and victims (Figure 3a,b,c,d), aroused feelings of dismay. Nevertheless, the show had the hypnotic "charm" of the disasters and could be replicated at will with a few turns of a dial.
In this work, we describe the stereoscopic viewer, the places depicted in the stereoscopic plates, and the seismic phenomena that caused the disasters exhibited. But above all, we investigate the social and cultural aims that prompted to show the effects of earthquakes through this primitive multimedia mechanism.
We wonder if the taxiphote, with its photographic equipment, was only an instrument of entertainment pour épater les bourgeois 1 , or rather if it carried out an informative task, to spread the knowledge of the recurrent seismic crises which Calabria and Sicily are prone.
We highlight that contemporary Central European literature offers us the opportunity to compare the educational purpose of the stereoscopic viewer with that of earthquake fiction in an amusement park.

The taxiphote model
The taxiphote consists of a wooden box in the shape of a rectangular parallelepiped (Figure 1, 2). In the upper part of the box, there is a pair of biconvex eyepieces with a focusing device, similar to opera glasses. They have the function of providing an enlarged view of the images placed at the focal distance. Inside the box, there is a rack that can be loaded with a few dozen transparencies on a glass plate. A rotating mechanism controlled by a knob allows to position each transparency in front of the eyepieces. On the side of the box opposite the eyepieces, there is a small window that allows the illumination of the transparency through a light source.
The taxiphote represented a more evolved version of the stereoscopic viewers invented by the physicists Charles Wheaston and David Brewster in the first half of the 1800s and then perfected by many other inventors [Besso, 1879]. The first models of stereoscopic viewers worked with photographic prints on cardboard, that had to be loaded individually, one at a time ( Figure 4 a and b). In the taxiphote the revolving rack made it possible to observe, one after the other, dozens of slides without removing the eyes from the eyepieces (Figure 4 c).
Each transparency reproduces a couple of images of the same subject taken from two slightly different points of view, equivalent to the shift of perspective that we can perceive when we look at an object, alternating the vision with only one eye at a time (parallax effect). The observation of a couple of images through the eyepieces of the taxiphote creates a single virtual image that gives the observer the feeling of three-dimensionality [Ganot, 1887] ( Figure 5).
To make a stereoscopic plate it was necessary to use a camera with two lenses, separated by a space equivalent to the average interpupillary distance of human eyes: about 6 cm ( Figure 6). The use of the interpupillary distance similar to that of the eyes renders the stereoscopic effect well for subjects at distances of a few meters. The more distant the subject, the smaller the differences between the left and right images, the less the stereo effect (objects a few kilometers away, such as mountains, coastlines, etc., naturally appear less three-dimensional). The closer the object is, the more exasperated the three-dimensional effect will be. In certain photographic shooting situations, interpupillary distances other than 6 cm are used. For example, in aerial shots, the distance between the two images will be hundreds of meters, returning what in jargon is called the "giant's view" similar to what one would have when observing a scale model from above. As shown by Wright [1924], the 6 cm interpupillary distance is suitable for distances up to 5-20m.   [Ganot, 1887]. The stereoscope viewer has two positive curvature (magnifying) lenses m and n, as oculars. The pair of images A and B are inserted at the focus of the lenses. The two figures A and B represent two perspectives of the same object, with a deviation equal to the perspectives that the sight naturally receives with the right and the left eye. The focus point of the image is changed by the lenses from its short distance (about 30 cm) to a virtual distance at infinity. The observer thus could see a new tridimensional image C resulting from the juxtaposition of the images A and B.

Use of the stereoscope in seismology
The invention of the stereoscope was widely used in the field of entertainment, accompanying and enhancing the development of photography. But the applications in various scientific and didactic sectors were also remarkable [Brewster, 1856;Persico, 1932].
In the field of geology, and in particular, in macroseismic studies, the English engineer and seismologist Robert Mallet was the first to use the stereoscopic photographs. After the disastrous earthquake in Basilicata on December 16, 1857, Robert Mallet, during a long stay in Italy, instructed a professional photographer to make hundreds of images, many of them stereoscopic [Mallet, 1862;Ferrari, 2017], (Figure 7). With the help of these reproductions, Mallet developed and became a pioneer in the studies of "observational seismology", a discipline of which he was the founder [Ferrari and McConnell, 2005].
Subsequently, INGV and SGA edited the Italian edition of the same work [Mallet, 1862;Ferrari, 2004Ferrari, -2009 in two volumes edited by Graziano Ferrari. Both works have the advantage of re-proposing the entire collection of 156 images, 120 of which stereoscopic, that illustrate the effects of the 1857 earthquake in Basilicata.

Calabrian-Sicilian earthquakes between the 1800s and 1900s
Between the last decade of the 1800s and the first of the 1900s, Southern Calabria and North-Eastern Sicily ( Figure 8) were hit by four devastating earthquakes (Table 1).
The first three earthquakes, which occurred in the years 1894, 1905, and 1907, caused [Mallet, 1862;Ferrari, 2017]. determined). This earthquake was followed by a tsunami and, from a historical perspective, had the effect of relegating to the background the importance of other previous destructive earthquakes [Bertolaso 2008;Castanetto and Sebastiano 2007;Guidoboni and Valensise 2013;Rovida et al., 2016]. Images of ancient Calabrian-Sicilian earthquakes  Based on the subjects depicted, the transparencies can be divided into three main groups:

The transparencies-collection and its purpose
a) The largest group refers to the earthquake of 16 th November 1894, which destroyed dozens of small villages in Calabria and Sicily and of which the seismologist Mario Baratta wrote a specific work [Baratta, 1895]. The In the slides-collection of the taxiphote, there are no images relating to either the earthquake that occurred on 23 rd October 1907 and the great earthquake of Messina in 1908.
The quality of the slides and the glass support allows us to state that they were not produced serially by a specialized company, but rather handcrafted, as for the stereoscopic viewer itself. Even the captions of the images, handwritten with rather uncertain writing, denote craftsmanship.
Franco Foresta Martin et al.
8 Figure 9. Bagnara, Calabria. This slide shows the population, who survived the earthquake of 16th November 1894, crowding in front of the royal office for the distribution of food.
As previously written in the introduction, we exclude that the use of the stereoscopic viewer was limited to entertainment. We put forward the hypothesis that the re-proposal of 3D images of past earthquake damages contributed to avoiding the process of removing those disasters from the collective memory, encouraging the adoption of seismic prevention actions. Certainly, at that time, the lesson from the past could be learned only by an élite, that is the wealthy and culturally updated social class. Based on testimonies collected by the heir of the owner of the stereoscopic viewer (Maria Ada Muscolino Basile, personal communication), we know that he practiced the profession of a land surveyor, developing also projects for the construction of rural houses. Moreover, he was the first in his village (Scaletta Zanclea, near Messina) to build a house for his family by using reinforced concrete, in the early 1900s. Therefore, it is plausible that the stereoscopic viewer had informative and educational purposes, addressed to a vast group of relatives, friends, occasional acquaintances, and perhaps customers.

Macroseismic effects of 1894 & 1905 earthquakes
The images of the effects give a more complete view of the earthquakes, thus representing a useful complement to the written descriptions. The use of these images can be helpful, to confirm and refine the macroseismic intensities assessed in the places where they were taken. All available information should be used to estimate the intensity of past earthquakes.
Here In Figure 11, we show two examples for the 8 th September 1905 earthquake, M 6.7, maximum intensity MCS X.
The shaking was felt all over Southern Italy and a total of more than 8,000 buildings collapsed. The stereographic images come from the villages of Parghelia ( Figure. 11a) and Zammarò (Figure 11b). The corresponding descriptions are exemplifying: Parghelia, MCS X -The earthquake caused the almost total destruction of the village. Zammarò, MCS X -All the houses were almost completely destroyed.

Ethics and pedagogy of a photo-gallery of disasters triggered by natural phenomena 4.1 Devastating earthquakes: a matter of fate or improvidence?
More than a century after the realization of the viewer and the stereoscopic images that are the object of our study, we wonder if we should limit ourselves to interpret their use only as a pastime, good to animate some hours with friends in the living room or to attribute other purposes to this apparent social divertissement. Before formulating some answers, it is necessary to go back much further in time and to mention the cultural impact that the great Calabrian earthquake of 1783 had in Italy.
On 5 th February 1783, the territories bordering the Strait were struck by what is now considered the maximum earthquake recorded in the most recent history of Italy, whose epicenter has been localized south of Polistena in the province of Reggio Calabria and magnitude estimated at 7.1 Richter [Rovida et al., 2016]. Dozens of villages were completely razed to the ground and the two major cities of Calabria and Sicily, respectively Reggio Calabria and Messina, suffered serious damages. The estimated number of deaths is around 50,000 people. The first shock was the beginning of a sequence that lasted for weeks, with many destructive aftershocks and epicenters that migrated from Southern Calabria to Eastern Sicily and vice versa, each time aggravating the death toll and damages [Bertolaso, 2008].
The concepts expressed by the Enlightenment philosopher Jean Jacques Rousseau in 1755, at the time of the catastrophic Lisbon earthquake, were then repeated. We can summarize those concepts in a simple question: is it useless to ask whether the earthquake is the sign of divine punishment (in the 1700s century many people thought it so) when it is evident that man had concentrated vulnerable dwellings in areas naturally exposed to seismic Franco Foresta Martin et al. phenomena? [Tagliapietra, 2004]. The debate on what we call today seismic risk prevention had timidly begun but, except for some warnings in the new building regulations of the time, which suggested wooden reinforcement structures and adequate foundations, it made no substantial changes in the reconstruction criteria of the cities so severely struck.
Just over a century later, between the end of the 1800s and the early 1900s, when the same areas near the Messina Strait were repeatedly hit by the strong earthquakes that we described in the previous section, it was evident that the multitude of houses in the villages and poor neighborhoods of the cities were still built with mud-bricks mixed with sun-dried straw, held together simply by clayey sand; to make matters worse, those fragile constructions were almost devoid of foundations [Guidoboni and Mariotti, 2008].
And yet, some far-sighted exceptions there had been and would have risen to international fame at the time of the 1908 earthquake, becoming the subject of a postcard. It was the case of the villa of professor Cammareri in Messina that remained unscathed because it was built on a single floor, with stone-bricks and very thick continuous foundation walls [Campione, 2009] (Figure 12). In the general heavy destruction of the city, the Office of Civil Engineering pointed out that Cammareri's house was an example to be followed for the good quality of construction criteria [Sciacca, 2008].

Depict the dreadful to exorcise the fear
In the early 1900s, the catastrophic earthquake of 1783 was a distant memory, but the devastation caused by the most recent seismic crises returned to ring the alarm bells: they were proof that Calabria and Sicily could not escape recurring seismic threats.
We are inclined to believe that the function of the stereoscopic viewer with its peculiar image gallery was a stimulus, not only for increasing the awareness of the ineluctability of the earthquake but also for suggesting ways of living with it. The three-dimensional scenes of public buildings and collapsed houses, toponymic plaques hanging from the rubble of unrecognizable roads, provided the demonstration of the risks inherent to the places, and the spur to realize buildings capable to resist. It is not a coincidence that in those years the use of reinforced concrete began to spread in Italy [Nelva and Signorelli, 1990] and that the wealthier social classes resorted to the most solid construction techniques when they had to build new houses. On a more subtle psycho-pedagogical level, we can affirm that the gallery of images of cities and villages devastated by the recurrent seismic crises had a function similar to that of the fearsome characters in children's literature: that is, to depict the horrid to exorcise the fear [Benini and Malombra, 2010]. In the case under study, to rationalize the ancestral fear of the earthquake that shakes any certainty anchored to the ground. The literature of the early twentieth century offers an effective example in which this psycho-pedagogical function is performed by a stage fiction, in an amusement park. In the autobiographical novel "The tongue set free. History of a youth", written by the Nobel Prize (1981) for Literature Elias Canetti (1905Canetti ( -1994 (Figure 13), there is the intense page of a childhood memory that demonstrates how the terrifying representation of earthquakes was practiced for educational purposes.  [Canetti, 2011].
Therefore, one year after the December 1908 earthquake of Messina, in the Austro-Hungarian empire of Franz Joseph , the most serious seismic catastrophe of post-unitary Italy had already become a spectacle to represent in a children's amusement park. And, on the other hand, Elias Canetti testifies that, after that show, he finds confidence and serenity in a mighty tree, a metaphor for something solid and well-rooted in the ground, something that no earthquake will ever crash. The happy ending of Canetti's story seems to indicate, albeit metaphorically, the need to adopt anti-seismic criteria to make buildings capable of withstanding strong earthquakes and became solid and well-rooted like a tree.

Conclusions
The use of strong images of past earthquake damages, that can hit the feelings and beliefs of people living in earthquake hazard-prone areas, is a tool to increase the seismic risk perception. Its pedagogical purpose is to raise awareness about the necessity to build houses following seismic codes to avoid past disasters, so demonstrating the social function and the ethical value this form of geo-education may have for local communities. Developing and disseminating knowledge on earthquakes across society is essential to change how people perceive the risk, and to improve the way for preparing to resist future seismic events and to promptly react in case of an earthquake occurs.
Recovering and keeping alive the memory of past disasters is the first step to increase citizens' awareness of risks. Greater awareness means greater responsibility and therefore a more active attitude by citizens in the defense against risks, with the long-term effect of increasing the resilience of human communities.
A geoethical approach to reducing the seismic risk needs to rediscover cultural and technical traces in our history to better shape modern and more effective ways to change social risk perception and to improve mitigation action.

Dedication and Acknowledgements. Dedicated to the memory of the spouses Antonino Muscolino and Amalia
Andronico, owners of the stereoscopic viewer described in the text; with heartfelt thanks to their daughter Maria Ada Muscolino Basile, who made the apparatus available for this research. The authors are grateful to Dr. Graziano Ferrari for his valuable suggestions, and to the anonymous reviewers whose comments have improved this manuscript.