“An earthquake off the coast of south-eastern Sardinia in 1616”
Coastal towers of south-eastern Sardinia damaged by the 1616 earthquake
by Daniele Vacca
Doctor of Modern History
Collaborator of the Istituto di Storia dell’Europa Mediterranea (ISEM)
of the Consiglio Nazionale delle Ricerche – CNR di Cagliari
Introduction
One the most important features of European history in the XVI century is the military confrontation between the Spanish Crown, and the Ottoman Empire. However, during the last two decades, the two powers gradually lost interest in the Mediterranean, directing their attention to other geographical areas.
Spain had to struggle to defend its precious trades along the routes which crossed the Atlantic Ocean from attacks by English and Dutch vessels.
Moving most of the fleet over to the Atlantic coast, meant that piracy in the Mediterranean immediately increased, having being contained for years as a result of the constant patrol of the coasts by the Spanish navy.
An evident consequence was that trade, especially to and from Sardinia, suffered badly. This brought to the completion of a static defence system, based on coastal towers, which had been started in the previous decades, and the creation of the Administracion del Real.
Between 1591 and 1599 twenty-six towers were built, and the same amount was built in the following decade, i.e. the years immediately after the founding of the institute for the Administration of the towers.
As well as building a considerable amount of watch towers and the reconstruction of the existing medieval ones, which were either unused or in a bad state, the Administration had to face growing costs: increased ammunition and new artillery for the towers, the distribution of weapons to civilians and stocking large quantities of grain to face possible dangers, such as sieges which could have been laid to towers or towns.
All this was on top of the basic cost of the running of the defence system, such as the salaries, board and lodging for the soldiers and other people who worked on or for the towers.
Even if there were continuous rumours of the possibility of the mighty Turkish fleet preparing for an invasion of the Island, as well as strategic movements by the French navy, and in a later stage also Dutch and English corsairs, most of the problems along Sardinian coasts came from attacks by pirates from the Barbary Coast, which in the mean time had become more frequent.
Although the towers were not ultimately decisive in the overall defence system set up by the Crown, they did however represent some tangible advantages.
Firstly, the towers acted as a valid deterrent for enemy ships, and thanks to a visual communication system, they were able to give timely warnings to the main strongholds, while simultaneously giving the local population the opportunity to seek protection for themselves and their possessions.
Furthermore, there was a large number of towers along the coasts of the Island and they were administered by such an important institution as the Administracion del Real, which managed the whole running of the static defence system. Ultimately, this means that researchers have been left with a great quantity of useful documents.
One the most important features of European history in the XVI century is the military confrontation between the Spanish Crown, and the Ottoman Empire. However, during the last two decades, the two powers gradually lost interest in the Mediterranean, directing their attention to other geographical areas.
Spain had to struggle to defend its precious trades along the routes which crossed the Atlantic Ocean from attacks by English and Dutch vessels.
Moving most of the fleet over to the Atlantic coast, meant that piracy in the Mediterranean immediately increased, having being contained for years as a result of the constant patrol of the coasts by the Spanish navy.
An evident consequence was that trade, especially to and from Sardinia, suffered badly. This brought to the completion of a static defence system, based on coastal towers, which had been started in the previous decades, and the creation of the Administracion del Real.
Between 1591 and 1599 twenty-six towers were built, and the same amount was built in the following decade, i.e. the years immediately after the founding of the institute for the Administration of the towers.
As well as building a considerable amount of watch towers and the reconstruction of the existing medieval ones, which were either unused or in a bad state, the Administration had to face growing costs: increased ammunition and new artillery for the towers, the distribution of weapons to civilians and stocking large quantities of grain to face possible dangers, such as sieges which could have been laid to towers or towns.
All this was on top of the basic cost of the running of the defence system, such as the salaries, board and lodging for the soldiers and other people who worked on or for the towers.
Even if there were continuous rumours of the possibility of the mighty Turkish fleet preparing for an invasion of the Island, as well as strategic movements by the French navy, and in a later stage also Dutch and English corsairs, most of the problems along Sardinian coasts came from attacks by pirates from the Barbary Coast, which in the mean time had become more frequent.
Although the towers were not ultimately decisive in the overall defence system set up by the Crown, they did however represent some tangible advantages.
Firstly, the towers acted as a valid deterrent for enemy ships, and thanks to a visual communication system, they were able to give timely warnings to the main strongholds, while simultaneously giving the local population the opportunity to seek protection for themselves and their possessions.
Furthermore, there was a large number of towers along the coasts of the Island and they were administered by such an important institution as the Administracion del Real, which managed the whole running of the static defence system. Ultimately, this means that researchers have been left with a great quantity of useful documents.
Results of research
Thanks to a series of documents found in the archival Administration of the Towers, kept at the Archivio di Stato di Cagliari – section Antico Archivio Regio - it has been possible to rescue from oblivion an interesting story of which, until recently, there were only a few isolated and short testimonies.
The soldiers garrisoned in Sardinian coastal towers were in charge of the defence of coastal areas and inland areas, but their main task was to report to the nearest tower possible attacks by pirates or corsairs. They also contributed to the defence of the population and property in small villages that were located along the coast of the island. In particular, the towers built in the south of the island, i.e. those built to the east and west of the Gulf of Cagliari, had as their principal function the protection of fortress of Cagliari, capital of the Kingdom of Sardinia, or as it was then called by the Spanish, Castel de Càller.
The seismic event occurred 4 June 1616 (saturday), as reported by the parish priest of Selargius Francesco Mirò, in the first volume of the town's Quinque Libri, kept in the Archivio Arcivescovile di Cagliari - quoted by Salvatore Loi in his book Cultura Popolare in Sardegna tra ‘500 e ‘600.
The clergyman from Selargius: “priore y curat de dita villa de Sellarjus”, gave notice that on 4 June at three o‘clock in the afternoon, there was a quake that shook the houses to the point that they seemed about to collapse.
The shock was indeed strong enough to shake everything and even people.
“1616, today Saturday, June 4, 1616 of this year, three in the afternoon there was a earthquake that shook houses, which seemed to collapse and the earth trembled so that people and all the houses trembled. Our God have pity and mercy of all us, Amen. I Francis Mirò, pastor and prior of the villa Selargius, confirm what was said on that earthquake. day and year on those.”.
He also mentions another seismic event occurred at five o’clock on 24 June 1617, St John's day, exactly a year after the previous one.
1617. Today, June 24, saturday, the day of Saint John this year 1617, at five after lunch another earthquake happened, the same as what was noted above, our Christ would have mercy on us. Amen.
The earthquake of 1616 was also cited by canon Giovanni Spano in his Guida della città di Cagliari, in the description he makes of the Cathedral of Santa Maria.
In the sacristy it is possible to read the information: «sopra la porta che conduce al Coro avvi una rozza ma ben concisa iscrizione» (over the door leading to the choir starts a rough but very concise inscription).
According to the author - but apparently he was wrong - this was the only testimony in which the exceptional event was remembered.
The inscription contains the following brief words: «A. D. 4 Iunii terremotus factus est.1616» (on 4 June 1616 A.D. there was an earthquake).
The news of the earthquake is also mentioned in Atlante della Sardegna, A. Pracchi and A. Terrosu Asole (eds.), the essay written by Furreddu, Tavola 2, Magnetismo e Sismicità (The seismic paper, in “Table 2, Magnetism and seismicity”).
The event is also briefly mentioned in a study by the National Group for Defense from the hydrogeological disasters, in the CNR project AVI: “Aree Vulnerate da calamità Idrogeologiche” (areas vulnerable to hydro-geological disaster), achieved at national level between 1992 and 1993.
In its final report, the research outlines 8 earthquakes on the island throughout history, including two in the twentieth century. Among these, the oldest is precisely that of 1616.
In more recent publications the event is partly mentioned. However, the reference to these documents is superficial and the earthquake was not given the importance it deserved, nor did it lead to a thorough multidisciplinary, scientific approach, which such a disastrous phenomenon would normally foresee.
An initial dissemination of the quake was carried out during the works of the meeting 'Sardinia: Mediterranean Crossroads, 12th Annual Mediterranean Studies Congress’. In this publication the author seeks to deepen his doctoral thesis.
Throughout the correspondence examined for the study of the event that hit south-eastern Sardinia, it is clear that the restoration was urgently required in order to repair the severe damage suffered by the eight coastal towers during the 1616 earthquake.
Linking these testimonies of the same phenomenon relative to different areas, namely Selargius, the Villasimius coast and Cagliari, helps to understand the scope and to start a rigorous study that takes into account historical and geological knowledge, as well as the common belief that Sardinia is a stable and aseismic region.
In none of the documents taken into consideration there is reference to any injuries or deaths caused by this earthquake.
However, according to the testimony of the parish priest of Selargius, the earthquake 1616 was certainly not a low-intensity one, in fact, the damage suffered by the eight towers along the south-eastern coast of the island were quite patent and serious, as evidenced by the memorial drafted by the Public corredor (auctioneer) who had published an open call for tenders.
Proceeding from the most northern part of the south-east coast, leading towards the capital of the Kingdom of Sardinia, Cagliari, the towers which were hit are the following: torre di Cala Pira in the present-day town of Castiadas , torre di San Luigi o dell’Isola di Serpentara in Villasimius, torre di Porto Giunco in Villasimius, torre dell’Isola dei Cavoli in Villasimius, torre di Cala Catalina o Caterina, in Villasimius, torre di Capo Boi in Sinnai, torre di Monte Fenugu in Maracalagonis, torre di Cala Regina in the administrative area of Quartu Sant’Elena.
The towers were heavily damaged, some apparently due to the effects of the earthquake, as outlined in the historical documents examined, others not explicitly stated, but of such an entity, which could not have been possible only due to the lack of routine maintenance. Others still, however, were most probably caused by negligence, erosion and, in some cases, the poor quality of the materials used. It was in fact common practice, even in those years, to use sea sand mixed with sea water, despite this being in breach of the laws of the time. This made the structure much weaker, while hampering its solidity.
Proceeding from the most northern part of the south-east coast, leading towards the capital of the Kingdom of Sardinia, Cagliari, the towers which were hit are the following:
1 - Torre di Cala Pira
2 - Torre dell’Isola di Serpentara
3 - Torre di Porto Giunco
4 - Torre dell’Isola dei Cavoli
5 - Torre di Cala Caterina
6 - Torre di Capo Boi
7 - Torre del Monte Fenugu (Torre delle stelle)
8 - Torre di Cala Regina
The works to be performed in each tower are indicated in the contract. In the first of these, e. g. in the tower of Cala Pira, it is interesting to notice that, besides a large number of interventions needed for its restoration, the tower had five major cracks on the outside walls: «Primo remediar les 5 fenadures que ha fet lo terremoto al derredor de la paret de dita fortalesa per que totes son molt grans» (initially, the five cracks caused by the earthquake all around the wall of that fortress must be repaired because they are all very large).
Furthermore, it was also necessary to urgently intervene on a number of important defensive elements of the tower, such as sentry boxes and some cracks in the ceiling, because of which water leaked through to the lower floors, making them unusable.
In particular, the arch under the vault needed to be repaired, as it was cracked from side to side.
An intervention to fill and re-arrange the floor, which in places had sunk two or three feet (considering that a Castilian palm was equal to 8,27 / 9,05 inches it can be said that the floor of the tower had collapsed in places of about 17,71 inches in other nearly 27,56 inches, but in the case of Sardinian palms, equal to 10,31 inches, the ground in the interior of the tower had collapsed 21,81 and 30,94 inches).
These reparations were followed by a series of further measures to improve the functionality of the tower, but most of them concerned the repair of damage resulting from the seismic event. Also specified in the contract were of course the materials that should have been used to make the restoration of the tower itself.
The other towers too suffered serious and significant harm; for brevity we have outlined only a few in this article, but a study is currently underway in order to publish all the documentation, with which it will be possible to access information about the damage suffered by all the towers involved in the earthquake.
«Primo remediar les 5 fenadures que ha fet lo terremoto al derredor de la paret de dita fortalesa per que totes son molt grans».
The soldiers garrisoned in Sardinian coastal towers were in charge of the defence of coastal areas and inland areas, but their main task was to report to the nearest tower possible attacks by pirates or corsairs. They also contributed to the defence of the population and property in small villages that were located along the coast of the island. In particular, the towers built in the south of the island, i.e. those built to the east and west of the Gulf of Cagliari, had as their principal function the protection of fortress of Cagliari, capital of the Kingdom of Sardinia, or as it was then called by the Spanish, Castel de Càller.
The seismic event occurred 4 June 1616 (saturday), as reported by the parish priest of Selargius Francesco Mirò, in the first volume of the town's Quinque Libri, kept in the Archivio Arcivescovile di Cagliari - quoted by Salvatore Loi in his book Cultura Popolare in Sardegna tra ‘500 e ‘600.
The clergyman from Selargius: “priore y curat de dita villa de Sellarjus”, gave notice that on 4 June at three o‘clock in the afternoon, there was a quake that shook the houses to the point that they seemed about to collapse.
The shock was indeed strong enough to shake everything and even people.
“1616, today Saturday, June 4, 1616 of this year, three in the afternoon there was a earthquake that shook houses, which seemed to collapse and the earth trembled so that people and all the houses trembled. Our God have pity and mercy of all us, Amen. I Francis Mirò, pastor and prior of the villa Selargius, confirm what was said on that earthquake. day and year on those.”.
He also mentions another seismic event occurred at five o’clock on 24 June 1617, St John's day, exactly a year after the previous one.
1617. Today, June 24, saturday, the day of Saint John this year 1617, at five after lunch another earthquake happened, the same as what was noted above, our Christ would have mercy on us. Amen.
The earthquake of 1616 was also cited by canon Giovanni Spano in his Guida della città di Cagliari, in the description he makes of the Cathedral of Santa Maria.
In the sacristy it is possible to read the information: «sopra la porta che conduce al Coro avvi una rozza ma ben concisa iscrizione» (over the door leading to the choir starts a rough but very concise inscription).
According to the author - but apparently he was wrong - this was the only testimony in which the exceptional event was remembered.
The inscription contains the following brief words: «A. D. 4 Iunii terremotus factus est.1616» (on 4 June 1616 A.D. there was an earthquake).
The news of the earthquake is also mentioned in Atlante della Sardegna, A. Pracchi and A. Terrosu Asole (eds.), the essay written by Furreddu, Tavola 2, Magnetismo e Sismicità (The seismic paper, in “Table 2, Magnetism and seismicity”).
The event is also briefly mentioned in a study by the National Group for Defense from the hydrogeological disasters, in the CNR project AVI: “Aree Vulnerate da calamità Idrogeologiche” (areas vulnerable to hydro-geological disaster), achieved at national level between 1992 and 1993.
In its final report, the research outlines 8 earthquakes on the island throughout history, including two in the twentieth century. Among these, the oldest is precisely that of 1616.
In more recent publications the event is partly mentioned. However, the reference to these documents is superficial and the earthquake was not given the importance it deserved, nor did it lead to a thorough multidisciplinary, scientific approach, which such a disastrous phenomenon would normally foresee.
An initial dissemination of the quake was carried out during the works of the meeting 'Sardinia: Mediterranean Crossroads, 12th Annual Mediterranean Studies Congress’. In this publication the author seeks to deepen his doctoral thesis.
Throughout the correspondence examined for the study of the event that hit south-eastern Sardinia, it is clear that the restoration was urgently required in order to repair the severe damage suffered by the eight coastal towers during the 1616 earthquake.
Linking these testimonies of the same phenomenon relative to different areas, namely Selargius, the Villasimius coast and Cagliari, helps to understand the scope and to start a rigorous study that takes into account historical and geological knowledge, as well as the common belief that Sardinia is a stable and aseismic region.
In none of the documents taken into consideration there is reference to any injuries or deaths caused by this earthquake.
However, according to the testimony of the parish priest of Selargius, the earthquake 1616 was certainly not a low-intensity one, in fact, the damage suffered by the eight towers along the south-eastern coast of the island were quite patent and serious, as evidenced by the memorial drafted by the Public corredor (auctioneer) who had published an open call for tenders.
Proceeding from the most northern part of the south-east coast, leading towards the capital of the Kingdom of Sardinia, Cagliari, the towers which were hit are the following: torre di Cala Pira in the present-day town of Castiadas , torre di San Luigi o dell’Isola di Serpentara in Villasimius, torre di Porto Giunco in Villasimius, torre dell’Isola dei Cavoli in Villasimius, torre di Cala Catalina o Caterina, in Villasimius, torre di Capo Boi in Sinnai, torre di Monte Fenugu in Maracalagonis, torre di Cala Regina in the administrative area of Quartu Sant’Elena.
The towers were heavily damaged, some apparently due to the effects of the earthquake, as outlined in the historical documents examined, others not explicitly stated, but of such an entity, which could not have been possible only due to the lack of routine maintenance. Others still, however, were most probably caused by negligence, erosion and, in some cases, the poor quality of the materials used. It was in fact common practice, even in those years, to use sea sand mixed with sea water, despite this being in breach of the laws of the time. This made the structure much weaker, while hampering its solidity.
Proceeding from the most northern part of the south-east coast, leading towards the capital of the Kingdom of Sardinia, Cagliari, the towers which were hit are the following:
1 - Torre di Cala Pira
2 - Torre dell’Isola di Serpentara
3 - Torre di Porto Giunco
4 - Torre dell’Isola dei Cavoli
5 - Torre di Cala Caterina
6 - Torre di Capo Boi
7 - Torre del Monte Fenugu (Torre delle stelle)
8 - Torre di Cala Regina
The works to be performed in each tower are indicated in the contract. In the first of these, e. g. in the tower of Cala Pira, it is interesting to notice that, besides a large number of interventions needed for its restoration, the tower had five major cracks on the outside walls: «Primo remediar les 5 fenadures que ha fet lo terremoto al derredor de la paret de dita fortalesa per que totes son molt grans» (initially, the five cracks caused by the earthquake all around the wall of that fortress must be repaired because they are all very large).
Furthermore, it was also necessary to urgently intervene on a number of important defensive elements of the tower, such as sentry boxes and some cracks in the ceiling, because of which water leaked through to the lower floors, making them unusable.
In particular, the arch under the vault needed to be repaired, as it was cracked from side to side.
An intervention to fill and re-arrange the floor, which in places had sunk two or three feet (considering that a Castilian palm was equal to 8,27 / 9,05 inches it can be said that the floor of the tower had collapsed in places of about 17,71 inches in other nearly 27,56 inches, but in the case of Sardinian palms, equal to 10,31 inches, the ground in the interior of the tower had collapsed 21,81 and 30,94 inches).
These reparations were followed by a series of further measures to improve the functionality of the tower, but most of them concerned the repair of damage resulting from the seismic event. Also specified in the contract were of course the materials that should have been used to make the restoration of the tower itself.
The other towers too suffered serious and significant harm; for brevity we have outlined only a few in this article, but a study is currently underway in order to publish all the documentation, with which it will be possible to access information about the damage suffered by all the towers involved in the earthquake.
«Primo remediar les 5 fenadures que ha fet lo terremoto al derredor de la paret de dita fortalesa per que totes son molt grans».
«Initially, the five cracks caused by the earthquake all around the wall of that fortress must be repaired because they are all very large »
di: Silvana Fais
Professore Associato S.S.D. GEO/10 - Geofisica della Terra Solida
Dipartimento di Geoingegneria e Tecnologie Ambientali di Cagliari
Considering the area affected by the seismological event and the geologic and geodynamic context of southern Sardinia, it is reasonable to deduce that the earthquake epicenter was located not far from the south-east coast of Sardinia and that its origin can be related to the geodynamics of the south Tyrrhenian Basin. The offshore area of the south-east Sardinia represents a very complex geological context wich was affected by many tectonic events. Therefore it is characterised from the presence of important faults in time reactivated.
Shows the geological-geostructural sketch of the area under study. Many faults of different orientation and different age are present testifying the complexity of the geological situation.
Since due to the lack of instrumental data we can only make deductions of a qualitative nature. Nevertheless considering the area affected by the seismological event and the geologic and geodynamic context of southern Sardinia, it is reasonable to deduce that the earthquake can be related to the geodynamics of the south Tyrrhenian Basin.
In any case, this hypothesis would need to be tested on the basis of studies of greater detail on the deep structural and volcanic features of the Gulf of Cagliari, which are in fact at present being carried out by the geophysical sector of the Department of Geoengineering and Environmental Technologies of the University of Cagliari (Italy).
shows as an example, the detailed analysis of an SW-NE interpretative geological section which transvers the offshore area of the Cagliari Gulf. This interpretative section was deduced from the interpretation of deep geophysical data. Specially it was the result of the interpretation of reflection seismic data like those used in hydrocarbons research, integrated with biostratigraphical and radiochronological information in the literature. From this section the complex tectonic structure of the Cagliari basin can be observed. The basin is constituted of tectonic blocks for the presence of important geological discontinuities (faults) evidenced in red colour in the section.
Considering the damage undergone by the towers one would be led to suggest an earthquake of an intensity of 6 or 7 degrees on the Mercalli scale, but the data would need to be related to the geological conformation of the area, to the building technique of coastal towers and to the quantity and quality of the building materials.
