Emanuela Guidoboni (SGA Geophysical Society-Environment, Italy) debate here about the Lisbon earthquake of 1755 and the earthquake in Calabria in 1783. Both earthquakes were of high intensity and were followed by tsunamis that significantly increased the high damage and loss of life. However, these two disasters were responsible for the beggining of the major building systems in the world of the eighteenth century with anti-seismic concerns: Gaiola Pombalina e a Casa Baraccata. Nowadays both building typologies are at risk to preserve their identity. The lessons that can be drawn from all historical earthquakes and the effects they can have in building activities, form the basis for preparation of cities to improve their seismic-resilience. These will be the aspects debated and discussed.
Less than thirty years after the Lisbon catastrophe, the centre and south of Calabria was struck by five devastating earthquakes between 2 February and 30 March 1783, reducing the area, in the description of contemporaries, to “a heap of rubble”. The destruction extended to Messina (Sicily), at the time an important trading centre. Historical research from the archives has brought to light the seismic areas activated and the whole scenario of effects in urban centres and villages, as well as the natural environment (landslides, fissures, liquefaction phenomena, the creation of new lakes and complete re-routing of rivers).
|ENGRAVING SHOWING "O TEJO", THE MOUTH AND THE TSUNAMI, LISBON 1755 (WIKIPEDIA)|
This highly complex seismic sequence also caused a tsunami in the Straits of Messina. Aftershocks in their hundreds went on for some four years. Such a sequence nowadays would be devastating in its impact, given the demographic density and the poor quality building of modern Calabria. The entire area thus stands at high seismic risk. Portugal’s 1755 experience was partly drawn on when it came to designing new housing in 1784 (from the gaibola to the casa baraccata).
New Calabrian townships were designed to a regular grid plan with broad streets and low-rise buildings to increase seismic resistance. New building regulations were issued by the Bourbon government, but then not enforced. A decade later in 1799, the anti-Bourbon uprising overthrew the government: amid institutional weakness and political/social strife, the anti-seismic project fell into abeyance. A kind of amnesia descended on the earthquake issue, for which later generations would pay dearly when quakes struck the region once more. Historical analysis of this crucial seismic sequence embraces scientific, townplanning and cultural aspects of this disaster.
VUE DE L'OPTIQUE COMPOSITION (HAND COLORED COPPER ENGRAVING USED IN THE LATERNA MAGICA TECHNIQUE) SHOWING SEA SHIPS AND BOATS ENDANGERED IN THE ROUGH WATERS OF THE MESSINA STRAIT DISTURBED BY THE 1783 EARTHQUAKE. FROM HISTORY OF GEOLOGY
After the 1755 disaster, the Calabrian earthquake fired European awareness of man’s risky relationship with nature and prompted scientific debate as to the causes of earthquakes and their relation with habitation patterns. The event seared the entire Bourbon kingdom of Naples; and with it the whole late-eighteenth-century spirit of Europe. That long seismic sequence in Calabria was made up of five violent earthquakes. The devastating impact marked an epoch in the region’s economic, social and cultural life. On February 5th 1783 a series of tremors began that would last more than three years. The five peaks of maximum intensity came on February 5th (M 6.9), 6th (M 6.2), 7th (M 6.4); and March 1st (M 5.6) and 28th (M 7.0).
These five quakes were preceded and followed by several hundred lesser tremors – at times hardly lower in force. The cumulative effect of this seismic upheaval was to destroy thousands of square kilometres of territory. The destruction extended from Central Calabria to Messina (Sicily), at the time an important Mediterranean trading centre. Historical research on administrative documentation (State Archives, Catanzaro and Naples), letters, reports, field reconnaissance and treatises, has pinpointed the seismic areas activated and the whole scenario of effects in urban centres and villages, as well as in the natural environment. In less than two months a number of North-South oriented faults became active along the Apennine chain.
Destruction was almost total in 182 villages (X and XI MCS), and in 33 of them the decision was to rebuild on another site. Some 300 other villages suffered serious damage and destruction (from VIII to IX). In the worst hit areas there were over 35,000 victims out of an overall population of about 400,000 (about 8% of residents). The earthquakes of 1783 shook an already precarious social order to the core. Infringements of law and order, dearth of housing and galloping epidemics were accompanied by a general conviction that a point of no return had been reached. The impact on the natural environment was so direly spectacular that scientists and naturalists of the day flocked to take note.
Landslides and slips, fissures and cleavages, newly-formed lakes and liquefaction phenomena were, for the first time, mapped and drawn as scientific documentation (the Schiantarelli e Stile Atlas, Accademia delle Scienze e Lettere, Naples, 1784). A far broader area was involved than the epicentres of the worst quakes. Whole hills slid into valley bottoms, sometimes dragging settlements with them, and blocked waterways, creating several hundred new lakes. On the night of the 5-6 February 1783 an enormous landslide crashed into the Tyrrhenian Sea near Scilla: waves of 6-8 metres in height struck the Calabrian coast and swept inland more than 160 metres, bringing new havoc and another 1,300 deaths.
|ENGRAVING SHOWING THE 1783 CALABRIAN TSUNAMI (WIKIPEDIA)|
The toll of this seismic cataclysm was not just villages, but urban centres important to economic and military life in the Kingdom of Naples and Sicily: towns like Reggio Calabria and Catanzaro, as well as Messina. The all-extensive desolation of Messina was described some years later by Goethe in his “Travels in Italy”: he called it a city of the dead. The extent of the area destroyed, which included some small relatively productive centres embedded in a large backward hinterland, prompted the central Neapolitan government to intervene.
Normally after a violent earthquake it would simply grant a few tax exemptions – unlike the previous Spanish government which set in motion a great work of reconstruction in eastern Sicily following the 1693 earthquake. The 1783 disaster was at once taken as an opportunity to try and redistribute resources, above all land ownership, and plan new towns and habitation patterns. The experience of Portugal certainly influenced these decisions, with her reforming drive to rebuild in the wake of 1755, powered by a flourishing mercantile economy since Lisbon was the capital of a colonial empire. But where were the funds to be found for Calabria, an outback of the Kingdom of Naples? In June 1784, spurred by Minister Caracciolo’s reform project, the Bourbon government launched a complex process of widespread expropriation of unproductive land belonging to the Church in Calabria.
These and certain baronial latifondi were impounded by a specific office called the Cassa Sacra. By administering and selling that patrimony, the government meant to finance the reconstruction of villages and also reboot the Calabrian economy via land redistribution. A new phase of development was envisaged for areas that had been marginal to the Kingdom’s social and economic life for centuries. New sites were chosen for rebuilding, townplanning projects were commissioned. The new plans make interesting viewing: they are star- or grid-shaped, with broad streets and buildings designed to dimensions and a regular pattern never seen before in Calabria
On the model of the Portuguese gaiola which came in after the 1755 disaster, a version incorporating a few variants was proposed: the casa baraccata, designed on a wooden framework with infill panels. Unlike the gaiola, the casa might be several storeys high and form part of the urban fabric. But after a few attempts to promote it, it was deemed an oddity (the prevailing building style in Calabria was stone or unbaked earth): an unduly expensive piece of modernism, the project was dropped. The bid to make good the laceration of the social and housing fabric fell short of expectations. Intellectuals and reformers of the period identified the causes of the widespread backwardness and poverty:
i) lingering feudalism: 83% of Calabrian territory was under baronial power;
ii) absentee landlords neglecting economic and production problems;
iii) a rapacious central tax system;
iv) state weakness vis-à-vis baronial and Church power;
Such factors were not removed and within a few years the newly-launched reconstruction scheme had failed. Only four of the many new towns intended were actually built. In the years that followed, another feature was exodus from the land towards the bigger towns. This only worsened an already severe shortage of labour on Calabrian farms. At least down to the mid-nineteenth century, the lost lives and crippled socio-economic life of Calabria due to the 1783 earthquakes made the region’s demographic development lag behind the other regions of the Kingdom of Naples.
The direct and indirect impact of that long seismic chain brought crisis on the manufacturing sector: the wool and silk industry at Palmi was sorely hit, and an epidemic of fevers set in on top of the earthquake. At Pizzo relatively few died under the rubble, but an ensuing epidemic caused many deaths among those camping on the beach for shelter. Some places, like Seminara, Oppido Mamertina and Briatico, suffered a recurrence of the fever epidemic in summer 1783 owing to malnutrition, poor hygiene and the prolonged privations. This epidemic alone caused nearly 19,000 deaths. A decade later in 1799, the anti-Bourbon uprising overthrew the government: amid institutional weakness and political/social strife, the anti-seismic project fell into abeyance. A kind of amnesia descended on the earthquake issue, for whicwhich later generations would pay dearly when quakes struck the region once more.
|MESSINA, 1908 AFTER THE TSUNAMI, HISTORY OF GEOLOGY|